In Secretary of State for Work and Pensions v Jwanczuk [2026] AC 699 [2025] 3 WLR 741 ('Jwanczuk'), the UK Supreme Court on 20.11.25, gave judgment on the issue of: '...the effect of judgments of appellate courts in the different jurisdictions of the United Kingdom...' (paragraph 55)(the 'Issue').
The judgment was given by Lord Reed PSC and Lady Simler JSC (with whom Lord Lloyd-Jones JSC, Lady Rose JSC and Lord Richards JSC agreed) and, at paragraph 55, it established, early on, some important points, that:
(1) the Issue '...concerns only a rule of practice. No party to these proceedings suggests that such judgments are formally binding.'
(2) what was in dispute between the parties in Jwanczuk, was '...only as to the weight which should be attached to them.', but
(3) 'Nonetheless, the [Issue] is one of considerable practical importance.' and that
(4) 'There is a major difference between treating a judgment with respect and treating it as one which should be departed from only in exceptional circumstances.'
Making point (1) above, Lord Reed PSC and Lady Simler JSC later stated:
(1) 'Scotland and Northern Ireland have distinct legal systems from that of England and Wales, with distinct hierarchies of courts.' (paragraph 58)
(2) 'A fundamental feature of the common law rules of precedent in each of the United Kingdom’s legal systems is that they are concerned only with the effect of decisions taken by courts within that legal system’s hierarchy of courts. An English court, for example, cannot be bound to follow a decision of a Scottish court, or vice versa.' (paragraph 59)
(3) '...the effect of a decision of an appellate court in one part of the United Kingdom on the decision of an appellate court in a different part of the United Kingdom is not a matter governed by the law of precedent....The question is governed by practice, not law.' (paragraph 92);
Similarly, in Marshalls Clay Products Ltd v Caulfield [2004] ICR 1502, Laws LJ said:
'...it would be a constitutional solecism of some magnitude to suggest that by force of the common law of precedent any court of England and Wales is in the strict sense bound by decisions of any court whose jurisdiction runs in Scotland only or-most assuredly-vice versa. Comity and practicality are another thing altogether. They exert a wholly legitimate pressure.' (paragraph 32)
Lord Reed PSC and Lady Simler JSC in Jwanczuk stated:
'Although decisions of courts in another jurisdiction do not normally fall within the scope of the doctrine of precedent, they may nonetheless influence a court’s decision for a variety of reasons, more than one of which may apply in any particular case. Without attempting an exhaustive list, in the first place their reasoning on a point of law may be found to be convincing, and may therefore be adopted Secondly, considerations of comity may exert pressure on a court, as Laws LJ put it, to follow the decision of a court in another jurisdiction. For example, the Inner House and the Court of Appeal will naturally treat each other’s judgments with great respect. Thirdly, in cases concerned with the interpretation of international conventions, courts will be influenced by the fact that it is important that their interpretation should be the same, so far as possible, in all contracting states: see, for example, Sidhu v British Airways plc [1997] AC 430. Fourthly, as Laws LJ acknowledged, considerations of practicality may exert pressure on a court in one jurisdiction to follow a decision of a court in another jurisdiction. That is illustrated by the case of Marshalls Clay Products Ltd v Caulfield itself, where Laws LJ said that “As a matter of pragmatic good sense the employment tribunal and the Employment Appeal Tribunal in either jurisdiction will ordinarily expect to follow decisions of the higher appeal court in the other jurisdiction (whether the Court of Session or the Court of Appeal) where the point confronting them is indistinguishable from what was there decided” (para 31).' (paragraph 60).
Accordingly, Lord Reed PSC and Lady Simler JSC stated:
'...as a matter of practice based on comity and good sense, rather than on legal rules of precedent, decisions of any of the appellate courts of England and Wales, Northern Ireland or Scotland will be treated as having persuasive authority when a similar legal point arises in one of the other jurisdictions. The weight which is attached to them will generally depend, in the first place, on how convincing the reasoning is found to be. Where practical problems are liable to result if the earlier decision is not followed, those will also be a relevant consideration. This general approach is familiar in areas of the common law where similar principles apply in each jurisdiction' (paragraph 61).
Later, they said '...there can be a range of factors which may affect the weight which should be given by one appellate court to another appellate court’s decision on a particular question' (paragraph 93)
This is the general approach but there are nuances to the law's approach. For example: (a) where revenue law is concerned; (b) where the matter involves the interpretation of legislation intended to apply in more than one of its constituent parts, or distinct but identical legislation, intended to apply in an identical way; and (c) Employment Appeal Tribunal, which is a single appellate tribunal applying identical legislation throughout Great Britain (subject to some minor exceptions), and exercising its jurisdiction on a Great Britain-wide basis.
The final appeal to the Supreme Court, where it exists, is the only common element to the Scotland, Northern Ireland, Wales and England legal systems, apart from tribunals whose jurisdiction extends to: (a) the whole of the United Kingdom, such as employment tribunals, or (b) the whole of Great Britain, such as the First-tier Tribunal (Social Entitlement Chamber) in social security and child support cases (paragraph 58).
Later, it was stated that, outside revenue legislation:
'...the best approach, as a matter of pragmatic good sense, is generally for the appellate courts of the United Kingdom to treat each other’s decisions on the interpretation of legislation with great respect, since it is undesirable that there should be conflicting decisions on the construction of provisions which are intended to apply in the same way in more than one jurisdiction. ...it may be appropriate to attach particular weight to another court’s view of the meaning of statutory language where it is difficult to say with any confidence that one interpretation is correct and another is wrong. Somewhat less weight may attach to another court’s interpretation of a similar but different provision.
However, appellate courts should not regard themselves as being under an obligation to follow decisions which they consider to be wrong. They do not require to identify some other compelling reason for departing from a wrong decision. They do not have to identify exceptional circumstances. It is better that they should explain clearly why they consider the decision to be incorrect, give what they consider to be the correct decision, and grant leave to appeal to this court so that the difference of views can be resolved without undue delay.' (paragraphs 100 and 101)
One point: while Jwanczuk is a UK Supreme Court decision, and so binding on all parts of the UK (Northern Ireland, Scotland, Wales and England), this article is written from the point of view of England and Wales.
Review and Summary
In their judgment in Jwanczuk, Lord Reed PSC and Lady Simler JSC:
(1) undertook a very substantial review of the law in this area, from paragraph 55 to 91; and then
(2) provide a summary ('Drawing these threads together' - paragraphs 92 to 101).
Those short on time can jump straight to the summary.
Review
Lord Reed PSC and Lady Simler JSC, at paragraphs 56 to 91, said:
'English law has a well-developed doctrine of precedent, developed by the courts as part of the common law. Its rationale, and its most fundamental features, were explained by Lord Neuberger PSC in Willers v Joyce (No 2) [2018] AC 843, para 4:
“In a common law system, where the law is in some areas made, and the law is in virtually all areas developed, by judges, the doctrine of precedent, or as it is sometimes known stare decisis, is fundamental. Decisions on points of law by more senior courts have to be accepted by more junior courts. Otherwise, the law becomes anarchic, and it loses coherence, clarity and predictability. Cross and Harris in their instructive Precedent in English Law, 4th ed (1991), p 11, rightly refer to the ‘highly centralised nature of the hierarchy’ of the courts of England and Wales, and the doctrine of precedent is a natural and necessary ingredient, or consequence, of that hierarchy.”
As those observations indicate, and as Lord Neuberger went on to explain, the doctrine is seen in its simplest and most familiar form when applied to the hierarchy of courts. Under English law, for example, circuit judges are bound by decisions of High Court judges, the Court of Appeal and the Supreme Court. High Court judges are bound by decisions of the Court of Appeal and the Supreme Court. The Court of Appeal is bound by decisions of the Supreme Court. The position is more nuanced when it comes to courts of co-ordinate jurisdiction. For example, the Supreme Court can depart from its own previous decisions in circumstances where it is appropriate to invoke the Practice Statement (Judicial Precedent) [1966] 1 WLR 1234, but it has emphasised that, because of the importance of the role of precedent and the need for certainty and consistency in the law, it should be very circumspect before accepting an invitation to do so: Knauer v Ministry of Justice [2016] AC 908, para 23. On the other hand, the Court of Appeal is bound by its previous decisions, subject to limited exceptions: Young v Bristol Aeroplane Co Ltd [1944] KB 718, 729–730, approved by the House of Lords in Davis v Johnson [1979] AC 264.
Scotland and Northern Ireland have distinct legal systems from that of England and Wales, with distinct hierarchies of courts. The final appeal to the Supreme Court, where it exists, is the only common element, apart from tribunals whose jurisdiction extends to the whole of the United Kingdom, such as employment tribunals, or to the whole of Great Britain, such as the First-tier Tribunal (Social Entitlement Chamber) in social security and child support cases. Each legal system has its own rules in relation to precedent, which sometimes differ from those of English law. For example, the principles which apply under English law to the Court of Appeal, as set out in Young v Bristol Aeroplane Co Ltd, do not apply under Scottish law to the Inner House of the Court of Session or the High Court of Justiciary, which can review their own previous decisions, and sit in an enlarged constitution when they wish to do so.
A fundamental feature of the common law rules of precedent in each of the United Kingdom’s legal systems is that they are concerned only with the effect of decisions taken by courts within that legal system’s hierarchy of courts. An English court, for example, cannot be bound to follow a decision of a Scottish court, or vice versa. This was explained with great clarity by Laws LJ in Marshalls Clay Products Ltd v Caulfield [2004] ICR 1502, in rejecting an argument that the Employment Appeal Tribunal sitting in London (and also, by implication, the Court of Appeal) was obliged by law to follow a decision of the Inner House on the interpretation of employment legislation. In a judgment with which Judge LJ and Charles J agreed, he said (para 32):
“The rules of precedent or stare decisis cognisable here are given by the common law … They include refinements which teach where the edge of precedent is to be found, so that often the earlier decision can be distinguished. I need not go into those. The essence is that precedent confines the very power of the courts subject to it. It is not a rule of discretion or comity or anything of the kind. It is therefore of necessity a doctrine whose reach is limited to the jurisdiction in which the courts in question operate. The House of Lords is no exception; by statute its writ runs to three jurisdictions, and accordingly it binds the lower courts within each of those jurisdictions. Statute might also extend the scope of precedent, as was done by the European Communities Act 1972, part of whose effect is to give binding force over the national courts to decisions of the European Court of Justice (in matters within the latter’s proper competence) … But it is at least clear, and here is the point on this part of the case, that it would be a constitutional solecism of some magnitude to suggest that by force of the common law of precedent any court of England and Wales is in the strict sense bound by decisions of any court whose jurisdiction runs in Scotland only or - most assuredly - vice versa. Comity and practicality are another thing altogether. They exert a wholly legitimate pressure.”
Although decisions of courts in another jurisdiction do not normally fall within the scope of the doctrine of precedent, they may nonetheless influence a court’s decision for a variety of reasons, more than one of which may apply in any particular case. Without attempting an exhaustive list, in the first place their reasoning on a point of law may be found to be convincing, and may therefore be adopted. For example, this court not infrequently cites decisions of the Supreme Court of Canada and the High Court of Australia where their reasoning has been found to be persuasive; but they are not, of course, binding precedents. Secondly, considerations of comity may exert pressure on a court, as Laws LJ put it, to follow the decision of a court in another jurisdiction. For example, the Inner House and the Court of Appeal will naturally treat each other’s judgments with great respect. Thirdly, in cases concerned with the interpretation of international conventions, courts will be influenced by the fact that it is important that their interpretation should be the same, so far as possible, in all contracting states: see, for example, Sidhu v British Airways plc [1997] AC 430. Fourthly, as Laws LJ acknowledged, considerations of practicality may exert pressure on a court in one jurisdiction to follow a decision of a court in another jurisdiction. That is illustrated by the case of Marshalls Clay Products Ltd v Caulfield itself, where Laws LJ said that “As a matter of pragmatic good sense the employment tribunal and the Employment Appeal Tribunal in either jurisdiction will ordinarily expect to follow decisions of the higher appeal court in the other jurisdiction (whether the Court of Session or the Court of Appeal) where the point confronting them is indistinguishable from what was there decided” (para 31).
Accordingly, as a matter of practice based on comity and good sense, rather than on legal rules of precedent, decisions of any of the appellate courts of England and Wales, Northern Ireland or Scotland will be treated as having persuasive authority when a similar legal point arises in one of the other jurisdictions. The weight which is attached to them will generally depend, in the first place, on how convincing the reasoning is found to be. Where practical problems are liable to result if the earlier decision is not followed, those will also be a relevant consideration. This general approach is familiar in areas of the common law where similar principles apply in each jurisdiction: see, for example, Webb v Times Publishing Co Ltd [1960] 2 QB 535, 555–556, where Pearson J considered the persuasive effect of decisions of the Court of Session in the context of the law of defamation. The question which arises in this appeal is whether greater weight should be given to a decision, and if so, how much weight, where it concerns the interpretation or application of a statutory provision which applies in more than one jurisdiction, or where, as in the present appeal, distinct but identical statutory provisions apply in different jurisdictions.
In relation to this question, the practice of the courts has varied to some extent. It may be helpful to consider the differences, and the factors which have influenced practice, particularly in relation to different areas of the law.
It is clear, in the first place, that no strict obligation to follow decisions of courts of co-ordinate jurisdiction has been recognised by the Scottish or English courts in relation to criminal statutes applying across the United Kingdom. The point can be illustrated by cases concerned with the interpretation of legislation governing road traffic offences. There are examples of the High Court of Justiciary declining to follow decisions of the Court of Appeal and the Divisional Court: see, for example, Milne v M‘Donald 1971 JC 40 (declining to follow Butler v Easton [1970] RTR 109, a decision which was subsequently overruled by the House of Lords). There are also examples of the Court of Appeal declining to follow decisions of the High Court of Justiciary: see, for example, R v MacDonagh [1974] QB 448 (declining to follow Ames v MacLeod 1969 JC 1; the High Court of Justiciary in turn declined to follow R v MacDonagh in McArthur v Valentine 1990 JC 146 ). The High Court of Justiciary has also declined to follow decisions of the House of Lords: see, for example, Ritchie v Pirie 1972 JC 7 (declining to follow Rowlands v Hamilton [1971] 1 WLR 647, a decision which revealed - or created - a loophole which was subsequently closed by a legislative amendment). In that case, the court acknowledged that it was unfortunate if different interpretations were to be given to the same United Kingdom statute by the courts in Scotland and England, but added that it was also unfortunate that the relevant Scottish case law had not been before the House of Lords when Rowlands v Hamilton was argued and decided.
This approach to criminal statutes reflects the fact that there are two apex courts in the United Kingdom in relation to criminal law: the High Court of Justiciary in respect of Scotland, and the Supreme Court in respect of the rest of the United Kingdom. Neither can bind the other except in relation to devolution and compatibility issues, where the Supreme Court is, by statute, given the final say. Neither has regarded itself as being under any obligation to follow the decisions of the other if it considers them to be wrong. The same applies as between the High Court of Justiciary and the Court of Appeal, and would in principle also apply in relation to the Northern Ireland Court of Appeal.
Nevertheless, the importance of adopting a common approach to the same provisions, where that is possible, is well recognised. For example, in Ludriecus v Thomson 2009 JC 78, Lord Reed said (para 18):
“Where the provision is one which appears in a UK statute, and which has previously been interpreted by appellate courts in the other jurisdictions of the United Kingdom, this court will also treat those interpretations with great respect, since it is undesirable that there should be conflicting decisions on the interpretation of a provision which is intended to apply in the same way throughout the United Kingdom.”
In Barclay v Richardson 2013 JC 181, where the High Court of Justiciary decided to follow the decision of the House of Lords in Cracknell v Willis [1988] AC 450, Lord Eassie said that a decision of the House of Lords on the construction of a statute creating the same criminal offences throughout Great Britain “is of course very highly persuasive in this jurisdiction” (para 33). There was, however, no suggestion that the court was obliged to follow it, and it decided to do so, by a bare majority, only after concluding that the reasoning and conclusion reached by the House of Lords were correct.
Accordingly, this is a context in which considerations of comity and practicality strongly encourage the adoption of a common approach, but the Scottish and English courts will nevertheless diverge where they are unable to accept the correctness of each other’s decisions. The adoption of this approach has not caused practical problems in the administration of the criminal law, possibly because differences of interpretation have in practice occurred only in relation to relatively technical questions. Although motorists might be surprised to learn that the interpretation given to some detailed aspects of the Road Traffic Acts changes when they drive across the border between Scotland and England, they do not plan their behaviour on the basis of one interpretation or the other. The prospect that an English motorist in Scotland, familiar with Rowlands v Hamilton, might have believed that the consumption of several quick whiskies after an accident would render him immune from prosecution for drink driving is a remote one, and one would have no sympathy with the disappointment of such a motorist in any event. The issue which divided the English and Scottish courts in R v MacDonagh and McArthur v Valentine - whether a person who is controlling a car’s movement and direction is “driving” it within the meaning of the legislation even if he is not sitting in the driver’s seat and the engine is switched off - seems equally unlikely in practice to trouble motorists travelling from one jurisdiction to the other. The significance of these differences also has to be seen in the context of the much more profound differences between other aspects of the criminal law and criminal procedure of Scotland, on the one hand, and England and Wales, on the other hand, which have been accepted since the Union.
When it comes to questions of civil law, any differences between the approaches adopted by the intermediate appellate courts to legislation which applies across the United Kingdom can normally be resolved by an appeal to the Supreme Court. Indeed, the resolution of such differences is one of the justifications for the Supreme Court’s existence. Nevertheless, as in the criminal context, the desirability of a common approach to provisions which are intended to apply in the same way across different jurisdictions, where that can be achieved, is well recognised. For example, Scottish and English courts treat each other’s decisions on the application of common provisions of the Companies Act 2006, the Partnership Act 1890 and the Sale of Goods Act 1979 as persuasive, although not binding.
The Northern Ireland Court of Appeal, on the other hand, has at times described its approach in terms which suggest a stricter practice of following the decisions of the Court of Appeal of England and Wales. In M‘Cartan v Belfast Harbour Comrs [1910] 2 IR 470, 494–495, a decision of the Irish Court of Appeal, Holmes LJ said:
“It is true that, although we are not technically bound by decisions in the co-ordinate English Court, we have been in the habit, in adjudicating on questions as to which the law of the two countries is identical, to follow them. We hold that uniformity of decision is so desirable that it is better, even when we think the matter doubtful, to accept the authority of the English court, and leave error, if there be error, to be corrected by the tribunal whose judgment is final on both sides of the Channel [ie the House of Lords].”
That passage was quoted and accepted in Northern Ireland Road Transport Board v Century Insurance Co Ltd [1941] NI 77, 107 per Murphy LJ.
Some later judgments have described the practice in more qualified terms. In McGuigan v Pollock [1955] NI 74, 100, Porter LJ said that the court was “not bound to follow the English Court of Appeal”. In the same case, Black LJ said at p 106, under reference to the earlier authorities, that when “a doubtful point has been decided in a particular way by the English Court of Appeal our courts feel a natural hesitation about refusing to follow the English decision”. He added at p 107 that “perhaps this course is especially one to be followed when the matter at issue is not one of any broad legal principle but is really a question as to the construction to be placed upon somewhat obscurely worded statutory provisions”. That dictum was cited with approval by Carswell LCJ, giving the judgment of the Northern Ireland Court of Appeal in Beaufort Developments (NI) Ltd v Gilbert-Ash (NI) Ltd [1997] NI 142, 155, where the court decided, with some hesitation, to follow an earlier decision of the Court of Appeal as to the construction of a provision in a standard form of building contract, notwithstanding doubts as to its correctness. The English decision was subsequently overruled when Beaufort Developments was appealed to the House of Lords: [1999] 1 AC 266.
More recently, in In re Staritt [2005] NICA 48 Campbell LJ, giving the judgment of the court, said (para 21):
“It has been long established that while this court is not technically bound by decisions of courts of corresponding jurisdiction in the rest of the United Kingdom it is customary for it to follow them to make for uniformity where the same statutory provision or rule of common law is to be applied … This is not to say that the court will follow blindly a decision that it considers to be erroneous.”
In Breslin v McKevitt [2011] NICA 33 the court said that “it is the practice of this court to follow English Court of Appeal authority leaving it to the Supreme Court to correct the law if appropriate” (para 49).
The approach adopted in most of these cases appears to be that decisions of the Court of Appeal will be treated as highly persuasive, as a matter of practice, but will not necessarily be followed. The judgments in McGuigan v Pollock and Beaufort Developments suggest that decisions of the Court of Appeal are more likely to be followed where the issue concerns a detailed question of construction of legislation or other documents, rather than a broader question of legal principle. That makes practical sense, since it reflects the fact that interpreting a legislative provision often involves making a choice between two or more equally plausible constructions, in relation to which it is difficult to say with confidence that one construction is right and the other wrong. Similar reasoning has also influenced the approach adopted by this court and its predecessor to the review of its own precedents or those of the House of Lords: see, for example, R v National Insurance Comr, Ex p Hudson [1972] AC 944, 966 and 1024; R v G [2004] 1 AC 1034, paras 30–35. In such cases it can often be said, as Lord Mansfield CJ famously said in relation to mercantile law in Vallejo v Wheeler (1774) 1 Cowp 143, 153 that “it is of more consequence that a rule should be certain, than whether the rule is established one way or the other”.
One area of the law where a stricter approach has been adopted across all three jurisdictions, to the extent that practice has hardened into a rule, is revenue law. It is an area of the law in which detailed and technical questions of statutory interpretation frequently arise. It is also an area where uniformity of construction has long been recognised as being of particular importance. It is necessary, first and foremost, so that the incidence of taxation is the same throughout the United Kingdom, and the economic consequences of living or investing in one of its constituent parts rather than another are not subject to a divergence in the interpretation of revenue statutes by the courts of different jurisdictions. This is important both constitutionally, as one of the underpinnings of the coherence of the United Kingdom as a unitary state, and as a matter of legal certainty for taxpayers. A difference in approach to matters such as entitlement to capital allowances, or the application of value added tax, could have a major impact on businesses’ contractual arrangements and their investment decisions, and could have profound consequences for the viability of commitments which they have undertaken. The fact that there are now some differences in relation to income tax in different parts of the United Kingdom, as a consequence of legislative devolution, does not diminish the importance of the general principle. The scope for such variations is limited by legislation, and does not arise as a consequence merely of differences in judicial interpretation.
The importance of uniform interpretation of revenue statutes has long been recognised. In Comrs for General Purposes of Income Tax for the City of London v Gibbs [1942] AC 402, 414 (“Gibbs”), Viscount Simon LC said:
“in construing a taxing statute which applies to England and Scotland alike, it is desirable to adopt a construction of statutory words which avoids differences of interpretation of a technical character such as are calculated to produce inequalities in taxation as between citizens of the two countries. Lord Halsbury LC affirmed this principle in Comrs for Special Purposes of Income Tax v Pemsel [1891] AC 531, 548, when he adopted the canon of construction laid down by the Court of Session in Baird’s Trustees v Lord Advocate (1888) 15 R 682, and quoted the general principle of common sense which Grose J laid down in a rating case ( R v Hogg (1787) 1 TR 721, 728): ‘an universal law … cannot receive different constructions in different towns.’ Lord Watson in Pemsel’s case [1891] AC 531, 557, deduces from the Scottish decision of Lord Saltoun v Lord Advocate (1860) 3 Macq 659 the principle, which he there applies, that the Income Tax Act 1842 must, if possible, be so interpreted as to make the incidence of its taxation the same in both countries.”
The authorities cited by the Lord Chancellor, and the case of Gibbs itself, were concerned with the proper approach to the construction of revenue statutes rather than with the authority of decisions of courts in different parts of the United Kingdom. However, the importance of following such decisions, in order to achieve a uniform interpretation of such legislation, has also long been recognised: see, for example, In re Hartland [1911] 1 Ch 459. It has been reflected in modern times in a strict adherence by the Court of Appeal to decisions of the Inner House, and vice versa, so far as they concern the construction of such legislation, and are neither per incuriam nor dependent on some special feature of Scottish or English law.
The leading authority on the point is Abbott v Philbin [1960] Ch 27; [1961] AC 352. The case concerned the tax treatment of a share option. The question was whether a charge to income tax under Schedule E to the Income Tax Act 1952 arose as soon as the option was granted or when the option was exercised. In an earlier case, the Inner House had favoured the latter result. When the question came before the Court of Appeal, Lord Evershed MR set out the grounds on which he found the reasoning of the Scottish court unconvincing. He did so, he explained, “because I have thought that, if this matter were to go further, it might be of some assistance if I were to state them” (p 46). However, the decision of the Inner House could not be treated as per incuriam, and it did not depend on any special feature of Scots law. In those circumstances, the Master of the Rolls considered that the Court of Appeal ought to treat the Scottish case as governing its decision. He explained (p 49):
“It is, of course, quite true that we in this court are not bound to follow the decisions of the Court of Session, but the Income Tax Act and the relevant Finance Acts apply indifferently both north and south of the border, and if we were to decide those questions in a sense diametrically opposite to the sense which appealed to the Scottish judges, we should lay down a law for England in respect of this not unimportant matter which would be completely opposite to the law which was applied, on exactly the same statutory provisions, north of the border. I cannot think that that is right. In a case of a revenue statute of this kind it is the duty of this court, unless there are compelling reasons to the contrary, to say, expressing such doubts as we feel we ought to do, that we should follow the Scottish decision.”
In short, Lord Evershed MR believed that the correct course was to express his doubts and leave it to the House of Lords, if an appeal were pursued, to decide whether they were well founded. Harman LJ gave a judgment to similar effect, saying in relation to the Scottish decision that “for reasons of policy it would not be right that this court should express a diametrically opposite view” (p 52). Sellers LJ said that he did not share Lord Evershed MR’s doubts about the correctness of the Scottish decision. The court gave leave to appeal to the House of Lords.
The approach adopted by the Court of Appeal to the earlier Scottish decision was explicitly approved in the House of Lords, which by a majority of three to two allowed the appeal and overruled that decision. Viscount Simonds said that the Scottish case was not in any material respect distinguishable, and that the Court of Appeal took the proper course in following it (p 368). Lord Reid said that the Court of Appeal, “though not bound to do so, very properly followed the decision of the Court of Session … I say very properly, because it is undesirable that there should be conflicting decisions on revenue matters in Scotland and England” (p 373). Parliament subsequently legislated to reverse the decision of the House of Lords, and reinstated the approach which had been adopted in Scotland.
The approach adopted in Abbott v Philbin has been applied in many subsequent cases concerned with revenue law: see, for example, Secretary of State for Employment and Productivity v Clarke Chapman & Co Ltd [1971] 1 WLR 1094, and R (DK) v Revenue and Customs Comrs [2022] 4 WLR 23. As far as the authorities cited to this court disclose, it was not until recently applied in any other area of the law. For example, in Flemming v Secretary of State for Work and Pensions [2002] 1 WLR 2322, a case concerned with the interpretation of social security legislation, the Court of Appeal expressed its agreement with an earlier decision of the Northern Ireland Court of Appeal concerned with the interpretation of similarly worded legislation, but did so only after carrying out its own analysis of the provision in question, and without attaching any special weight to the Northern Irish decision.
However, in Deane v Secretary of State for Work and Pensions [2011] 1 WLR 743 (“Deane”), a case concerned with the same social security legislation as was in question in Flemming, the Court of Appeal considered that the approach taken to revenue legislation in Abbott v Philbin should in principle be adopted much more widely. Ward LJ, giving the only reasoned judgment, said in relation to decisions of the Northern Ireland Court of Appeal (para 26):
“Where the decision relates to a statutory requirement which applies or which is the same as that which applies in England and Wales, then we ought to follow that court in order to prevent the wholly undesirable situation arising of identically worded legislation on the other side of the Irish Sea (or the other side of the Tweed) being applied in inconsistent ways. The same approach as we adopt for cases of the Court of Session in Scotland should be followed in the case of Northern Ireland.”
Ward LJ then cited Abbott v Philbin as exemplifying the approach adopted for cases decided by the Court of Session.
Applying authorities concerned with the English law of precedent, Ward LJ considered that the Court of Appeal was “not obliged to follow” the Northern Irish decision in the case before the court if the point in issue was conceded or did not form part of the ratio decidendi. After carrying out an examination of the reasoning of the Northern Ireland Court of Appeal, he concluded that the views which had been expressed on the point in issue were obiter dicta, and that the Court of Appeal was therefore not obliged to follow them.
We are unable to accept Ward LJ’s reasoning in this case. We note in the first place that since the point in issue had not in fact been decided by the Northern Ireland Court of Appeal, it follows that Ward LJ’s discussion of decisions relating to statutory requirements which apply or which are the same as those which apply in England and Wales was itself obiter. Secondly, although Ward LJ quoted Lord Evershed MR’s dictum confining his remarks in Abbott v Philbin to “a case of a revenue statute of this kind” (para 75 above), and Lord Reid’s statement that “it is undesirable that there should be conflicting decisions on revenue matters” (para 77 above), he did not advert to the fact that the case before the court was not concerned with revenue law and might not give rise to equally cogent practical considerations. Thirdly, he appears to have treated the exercise on which he had embarked as one arising under the law of precedent, and as requiring the application of the rules developed by judicial decisions in that area of the law. However, as we have explained, this is not a question of the common law of precedent, but rather of practice based on comity and practical good sense.
In the present case, Kerr J said that he was guided by Ward LJ’s judgment in Deane (para 46). He noted that the point in issue concerned the content of Convention rights, rather than a question of statutory construction. However, as explained above, he accepted that “Human rights should, if possible, have the same content throughout the UK”. Accordingly, if the decision of the Northern Ireland Court of Appeal in O’Donnell was not distinguishable, he would not depart from it unless persuaded that it was “clearly wrong”, which he would find “only with great diffidence” (para 47). He accepted that he had to consider the arguments afresh, as “it would not be right to decide this case only on the basis that O’Donnell stands as authority against the [Secretary of State]” (para 75). Having done so, he found himself in agreement with the conclusion reached in O’Donnell, although not with all of the reasoning.
On appeal, the Court of Appeal adopted an approach based on Abbott v Philbin and Deane. Underhill LJ, giving a judgment with which the other members of the court agreed, noted that Abbott v Philbin was concerned with revenue law, and Deane with social security legislation, but said that the difference was not material (para 41). He noted that Lord Evershed MR had said that in “a case of a revenue statute of this kind” it was the duty of the Court of Appeal, “unless there are compelling reasons to the contrary”, to follow the earlier decision of a court of co-ordinate jurisdiction. As to what might amount to compelling reasons, Underhill LJ considered that “it will require more than mere disagreement with the decision of the first court” (para 44), since that was the position in Abbott v Philbin itself. In his view, “the minimum requirement for a ‘compelling reason’ must be that the second court believes that the first court’s decision was clearly wrong, where the word ‘clearly’ connotes a heightened threshold” (ibid). He could conceive that in some circumstances, substantial differences in the evidence adduced or the points argued before the two courts, at least where the differences were fundamental, might be sufficient to justify a departure from the Abbott v Philbin rule, but generally courts should be very slow to take that course. The policy reasons for maintaining a uniformity of approach between the jurisdictions applied even if there were differences in how two cases were presented (para 45). Although Underhill LJ went on to identify some difficulties in relation to the reasoning in O’Donnell, he did not think it right to develop the points, still less to express any concluded view, because he did not believe that the case before him came close to being “a case of the exceptional kind” where, applying the Abbott v Philbin rule, it would be right to decline to follow O’Donnell (para 105).
Underhill LJ noted that his conclusion accorded with the decision of a tribunal of social security commissioners in R(SB) 1/90 Reported Decisions of the Social Security Comr, vol XIII (1989–1990), p 637, which had been cited with approval by Ward LJ in Deane. In their judgment, the commissioners said that, since a decision of a commissioner sitting in England and Wales on a Scottish matter could be appealed to the Court of Session, and a decision of a commissioner sitting in Scotland on an English matter could be appealed to the Court of Appeal, it followed that “pronouncements on common provisions, whether made by the Court of Appeal in England or the Court of Session in Scotland, must be followed, as of necessity rather than for reasons of comity, by all Commissioners of Great Britain” (para 12; emphasis in original). In other words, it seems, decisions of the Court of Appeal were legally binding on tribunals sitting in Scotland, and decisions of the Court of Session were binding on tribunals sitting in England and Wales. That view is incorrect, as we explained at para 59 above.
The tribunal recognised that the position was different in relation to Northern Ireland, with which the case before it was concerned, as the province had a separate body of social security legislation, and there was no possibility of a decision taken in Northern Ireland being appealed to the Court of Appeal or the Court of Session, or of a decision taken in England and Wales or in Scotland being appealed to the Northern Ireland Court of Appeal. However, it said, “there has long been a tradition in this country that, where the same Act applies both in England and Scotland, but where, unlike the case of social security legislation, there is no interchange of function between adjudicating authorities resident in each country, then in the interest of comity there should be uniform interpretation” (para 13). As authority for this tradition the tribunal cited the tax cases of In re Hartland and Abbott v Philbin. Although the social security legislation in force in Northern Ireland was distinct from that in force in the rest of the United Kingdom, the tribunal considered that “where the relevant provisions are identical (as they are in this case), the same judicial approach should equally be adopted” (para 15).
Underhill LJ was not referred to authorities demonstrating that a different approach has been adopted in relation to the Employment Appeal Tribunal, which is a single appellate tribunal applying identical legislation throughout Great Britain (subject to some minor exceptions), and exercising its jurisdiction on a Great Britain-wide basis. We cited earlier the decision of the Court of Appeal in Marshalls Clay Products Ltd v Caulfield, which emphatically rejected an argument, based on Abbott v Philbin, that the Employment Appeal Tribunal sitting in one part of Great Britain ought, as a matter of law rather than pragmatic good sense, to treat the decisions of an appellate court in the other part of Great Britain as binding precedents. On that basis, the court rejected a submission that the tribunal, sitting in London, had erred in law by declining to follow a decision of the Inner House.
Subsequently, in Airbus UK Ltd v Webb [2007] ICR 956 the Employment Appeal Tribunal, sitting in London, observed per Elias J (President) that although it was not bound by the decisions of the Inner House, pragmatic good sense would suggest that it should ordinarily follow them, “even where there may be narrow grounds for distinguishing the Scottish case” (para 57). In hearing appeals against decisions of the Employment Appeal Tribunal, the Inner House has also adopted the position that it should follow a relevant decision of the Court of Appeal, against which the Supreme Court has refused permission to appeal, “unless there are compelling reasons suggesting otherwise”: Amery v Perth and Kinross Council [2012] ICR 1067, paras 35 and 50.
The authorities were reviewed by the Employment Appeal Tribunal, sitting in England, in the recent case of Augustine v Data Cars Ltd [2025] ICR 19. The case concerned a question on which there were conflicting decisions of the tribunal, and also a decision of the Inner House. Eady J (President), giving the judgment of the appeal tribunal, explained that, if they were approaching the question absent any prior judicial consideration, they would not hesitate to adopt a different view from the Inner House (para 67). However, citing the judgment of Laws LJ in Marshalls Clay Products Ltd v Caulfield, she said (para 82):
“Although the decision [of the Inner House] does not bind us as a matter of law, we consider that there is a compelling case for not departing from what has been acknowledged to be good practice, whereby the EAT - which has a Britain-wide jurisdiction - should ordinarily follow relevant decisions of higher courts within Great Britain, notwithstanding that the doctrine of precedent would not normally apply. Where, as here, the decision in question relates to a legislative protection that extends throughout Great Britain, and where there is no separate question as to the application of Scottish law, or the law of England and Wales, there is a legitimate public interest in consistency of approach. The fact that the issue raised by the present appeal has come before us by way of an appeal from an English ET is a matter of chance; as the case law makes clear, this is an issue that has arisen (not infrequently) in cases both north and south of the England/Scotland border. In these circumstances, we consider that the appropriate course is to approach this appeal on the basis that the decision [of the Inner House] is binding upon us.”
On an appeal against the appeal tribunal’s decision, a ground of appeal that it had erred in treating the Scottish decision as binding upon it was not pursued, in the light of the decision of the Court of Appeal in the present case. However, the correctness of the Scottish decision was argued before the Court of Appeal, which concluded by a majority (Elisabeth Laing LJ dissenting) that the decision was wrong: in the view of Bean LJ, “clearly wrong”: [2025] ICR 1404, para 101. Nevertheless, the Court of Appeal decided to follow it and dismiss the appeal.
Edis LJ said that he did so for the reasons given in Abbott v Philbin. He added that it was very important that the rules of precedent were applied in a way which avoided inconsistent decisions being reached in different jurisdictions. Bean LJ treated Abbott v Philbin as establishing a general principle, which he expressed as follows (para 101):
“We are not bound by the doctrine of precedent to follow decisions of the Inner House of the Court of Session or the Court of Appeal in Northern Ireland, but where either of those courts has given a decision on the meaning of a statutory provision applicable throughout Great Britain or throughout the United Kingdom it is highly desirable that this court should follow the previous decision and leave it to the Supreme Court to resolve the difficulties. That principle was established in the tax case of Abbott v Philbin [1960] Ch 27; [1961] AC 352 as one to be adhered to in the absence of what Lord Evershed MR described as ‘compelling reasons’.”
Bean LJ added that the result of the appeal would “leave the law relating to part-time workers in an unsatisfactory state, with tribunals both north and south of the border now being obliged to follow [the Scottish decision] despite … its obvious defects”. However, “Only a decision of the Supreme Court (or an amendment to [the relevant legislation]) can resolve the problem” (para 103).
In relation to the latter point, an appeal to this court would have been possible whichever way the case was decided by the Court of Appeal. We have also explained that the Inner House, unlike the Court of Appeal, is not bound by its previous decisions. Accordingly, if the Court of Appeal had departed from the decision of the Inner House and put the law of England and Wales on what it considered to be the proper footing, that would have addressed the situation in by far the larger jurisdiction. It would have been open to the Court of Session to review its own previous decision, if the point came before it in another case, and to overrule it if it thought fit, failing which an appeal might have been brought to this court.'
Summary
Lord Reed PSC and Lady Simler JSC in Jwanczuk, at paragraphs 92 to 101, said:
'Drawing these threads together, we reiterate in the first place that the effect of a decision of an appellate court in one part of the United Kingdom on the decision of an appellate court in a different part of the United Kingdom is not a matter governed by the law of precedent. That was clearly explained by Laws LJ in Marshalls Clay Products Ltd v Caulfield (para 59 above). The question is governed by practice, not law.
Secondly, we have explained that there can be a range of factors which may affect the weight which should be given by one appellate court to another appellate court’s decision on a particular question (para 60 above). However, in relation to decisions of courts in the United Kingdom on the interpretation of legislation intended to apply in more than one of its constituent parts, or distinct but identical legislation intended to apply in an identical way, we have explained that two factors are particularly important: first, how convincing the reasoning of the earlier decision is found to be, and secondly, whether practical problems are liable to result if it is not followed (para 61 above). Accordingly, deciding how much weight attaches to a decision in particular circumstances generally involves the exercise of judgement. The position is different only where the approach to be followed in relation to a particular type of case has become so well established that it amounts to a rule of practice.
Thirdly, legislation which applies across the United Kingdom (or Great Britain, as the case may be) must in principle have a single meaning, and must be designed to apply in the same way in different parts of the country. It is therefore sometimes said, as Edis LJ said in Augustine v Data Cars Ltd (para 90 above), that it is very important to avoid inconsistent decisions being reached in different jurisdictions. However, in principle it is even more important that statutory provisions should be interpreted correctly than that they should be interpreted consistently.
Fourthly, the practical importance of consistent interpretation depends to some extent on the nature of the legislative provision in question. Examples were given earlier (paras 63–66 above) of inconsistent interpretations of criminal statutes by Scottish and English appellate courts, which do not appear to have produced significant problems. The practical importance of a correct interpretation also depends on the nature of the provision in question. It was explained earlier (para 71) why it makes sense to be readier to follow decisions concerning detailed questions of interpretation, in circumstances where it is difficult to say which construction is correct and where certainty may be of greater practical importance than whether one construction is adopted or the other, than to follow decisions on broader questions of legal principle.
Fifthly, we have explained that there is a rule of practice in relation to the interpretation of tax legislation which is long established and has its roots deep in the past (paras 73–77 above). As we have explained (para 72 above), the strictness of the practice followed in such cases reflects particular characteristics of tax legislation, notably the constitutional and economic importance of uniformity across the United Kingdom as a whole.
In relation to legislation concerned with matters other than taxation, it cannot be assumed that a justification exists for following an equally strict practice. In Deane, in the present case, and in Augustine v Data Cars Ltd, it was simply assumed that the rule of practice laid down in relation to tax legislation applied equally to social security legislation, to Convention rights, and to employment legislation respectively. However, that cannot be assumed. Without underestimating the importance of a consistent approach to each of those areas of the law, to the extent that they are governed by legislation applying across the United Kingdom or Great Britain as a whole, it is not apparent that inconsistent decisions in any of those areas have the same potential to disrupt economic activity or legal certainty as inconsistent decision-making in relation to tax law.
Sixthly, it is necessary to bear in mind the implications of devolution, where devolved legislation is in issue in the earlier proceedings or in the proceedings currently before the court. It cannot any longer be assumed that similarly worded legislation enacted in different parts of the United Kingdom should necessarily be treated in the same way. There are different legislative and executive bodies, which may be acting for different reasons, and on the basis of different background material. Issues of justification under the HRA, in particular, generally depend on judgements about legislative choices made in the light of conditions in the jurisdiction to which the legislation applies, and the constitutional arrangements in place in that jurisdiction. A further consequence of devolution is that the government bodies which are party to proceedings concerned with legislation enacted by different legislatures may not be the same. For example, since O’Donnell concerned devolved legislation, the Secretary of State was not a party to the proceedings (although she might have applied to intervene). That is a further difference from Abbott v Philbin. In tax cases the revenue is inevitably party to the earlier proceedings as well as the proceedings currently before the court. It has therefore been heard before the decision is taken in the earlier proceedings, which will be followed in the later proceedings.
In the light of the various factors we have mentioned, the arguments presented to us do not in our view provide a justification for extending the scope of the strict approach adopted in Abbott v Philbin beyond the interpretation of tax statutes. In relation to that area of the law, the practice approved in Abbott v Philbin, and the factors affecting the scope of that practice as carefully described by Lord Evershed MR, have withstood the test of time.
In other areas of the law, it appears to us that the best approach, as a matter of pragmatic good sense, is generally for the appellate courts of the United Kingdom to treat each other’s decisions on the interpretation of legislation with great respect, since it is undesirable that there should be conflicting decisions on the construction of provisions which are intended to apply in the same way in more than one jurisdiction. As we have indicated, it may be appropriate to attach particular weight to another court’s view of the meaning of statutory language where it is difficult to say with any confidence that one interpretation is correct and another is wrong. Somewhat less weight may attach to another court’s interpretation of a similar but different provision.
However, appellate courts should not regard themselves as being under an obligation to follow decisions which they consider to be wrong. They do not require to identify some other compelling reason for departing from a wrong decision. They do not have to identify exceptional circumstances. It is better that they should explain clearly why they consider the decision to be incorrect, give what they consider to be the correct decision, and grant leave to appeal to this court so that the difference of views can be resolved without undue delay.'
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