Thwaite – The Jury Remains Out

In ‘The Thwaite jurisdiction – a stay of execution?’ published on the Financial Remedies Journal Blog on 21 November 2023, https://financialremediesjournal.com/the-thwaite-jurisdiction-a-stay-of-execution, Philip Tait and I traced the Thwaite jurisdiction from its origins through several cases including Benson v Benson (Deceased) [1996] 1 FLR 692 (per Bracewell J), L v L [2006] EWHC 956 (Fam), [2008] 1 FLR 26 (per Munby J as he then was), Bezeliansky v Bezelianskaya [2016] EWCA Civ 76 (per McFarlane LJ as he then was) concluding with H v W [2023] EWFC 120 (per HHJ Reardon) and AFW v RFH [2023] EWFC 119 (per Recorder Moys).

We concluded our article as follows:

‘So the jury is still out. Is Thwaite solely an equitable jurisdiction to refuse to enforce an executory order if in the circumstances prevailing it would be inequitable to do so or a power that extends to making a different order albeit (perhaps) one restricted to cases where there has been an element of deliberate frustration of the implementation of an unexecuted order by the actions of a party or third parties and where the case might fail the first limb of Barder on the basis that the events in question were foreseeable.

It is almost inevitable that this will be a question for the Court of Appeal to determine in due course. In the meantime it remains a problematic jurisdiction. As Michael Horton noted in “Setting aside executory orders: a terrible fate for Thwaite?”, [2018] Fam Law 884: “rely on Thwaite with care – at some point, an appellate court may well be asked to consign Thwaite to the history books”.’

In Collardeau v Fuchs [2025] EWFC 307, [2026] 1 FLR 461 from [40] onwards Poole J cited from (or referred to) Thwaite v Thwaite [1981] 2 FLR 280, L v L (which in turn cited from Benson v Benson (Deceased)), Bezeliansky v Bezelianskaya, Kicinski v Pardi [2021] EWHC 499 (Fam), [2022] 1 FLR 474 and BT v CU [2021] EWFC 87, [2022] 2 FLR 26 before stating as follows:

‘44 I proceed on the basis that it is now established that where an order is executory, meaning that it has not been implemented, and there has been a significant change in circumstances since the order was made, the Court has the power to vary the order if it would be inequitable not to do so.’

But has it been so established?

Origins of the jurisdiction

The Thwaite jurisdiction (unsurprisingly) has its origins in Thwaite v Thwaite. The parties negotiated a consent order on the basis that the wife agreed to return from Australia with the children and to live with them in England. The husband agreed to transfer a home for them to live in. The wife did return, but only for 3 months, and the husband refused to complete the property transfer. Ormrod LJ stated at p 284:

‘Where the order is still executory, as in the present case, and one of the parties applies to the court to enforce the order, the court may refuse if, in the circumstances prevailing at the time of the application, it would be inequitable to do so: Mullins v Howell (1879) 11 Ch D 763 and Purcell v F C Trigell Ltd [1970] 3 All ER 671 at 676–677, [1971] 1 QB 358 at 367–368. Where the consent order derives its legal effect from the contract, this is equivalent to refusing a decree of specific performance; where the legal effect derives from the order itself the court has jurisdiction over its own orders: per Jessell MR in Mullins v Howell (1879) 11 Ch D 763 at 766.’

In Thwaite, the Court of Appeal in fact went further than this and upheld the decision of the lower court not only to decline to enforce the unexecuted transfer of property order, but also to exercise its discretion to make a fresh order providing for sale of the property and division of the proceeds.

Ormrod LJ explained the rationale for this as follows at p 285:

‘The learned judge was entitled, in his discretion, to make a new order for ancillary relief in favour of the wife, notwithstanding the refusal of the wife to consent to his doing so. His jurisdiction arose, not from the liberty to apply as he held, but from the fact that the wife’s original application for ancillary relief was still before the court and awaiting adjudication. It had not been dismissed since the conveyance had never been executed, so that that part of the order … by which her application was dismissed, had never come into effect. We think that the judge correctly exercised his discretion in this respect.’

It is this second part of the decision that continues to cause controversy.

Consideration of the jurisdiction by the Court of Appeal

Bezeliansky, as with Thwaite, concerned an order made by consent that contained provision for property transfer; likewise it was a term of the order that upon transfer of the properties and division of other capital matters provided for in the order, there was to be a clean break between the parties; and likewise those transfers had not taken place.

At first instance Moor J was clearly aware of the conditional nature of the clean break arrangement that would only dismiss the parties’ claims for financial provision upon implementation of the property transfers. He said (as quoted at [22] of the appeal judgment):

‘… I am quite satisfied that I have that jurisdiction. It is right, in fact, to note that the clean break only takes place once there has been compliance with all of the orders that were made by Holman J, so in one sense there is still jurisdiction in any event to make an order under s 24(a) for a sale of the French property. But, I am equally satisfied that pursuant to Thwaite v Thwaite [1982] Fam 1, a decision of the Court of Appeal, an executory order can be varied in the way that Mr. Chamberlayne invites me to do.’

Moor J therefore set aside certain capital elements of the parties’ consent order and made a new property adjustment order (and an order for sale) in favour of the wife.

The appellant did not attend the appeal. His McKenzie Friend attended but was refused permission to address the court. Leading counsel appeared for the respondent. The appellant had, however, prepared a skeleton argument for the appeal, with the assistance of his McKenzie Friend, in which several submissions were made.

McFarlane LJ (as he then was) stated as follows:

‘31 … the husband submits that Moor J was wrong in his interpretation of the case of Thwaite v Thwaite (1981) 2 FLR 280. It is submitted that that authority dealt solely with the court’s jurisdiction to opt to refuse to enforce a consent order and that it is not authority in relation to there being any jurisdiction to set the original order aside.’

Thereafter he stated that:

‘37 It is plain to me that Moor J was entirely correct in holding that the authority of Thwaite v Thwaite to the effect that “an executory order can be varied in the way that Mr Chamberlayne invites me to do” was entirely sound and the appellant’s submission that the judge was wrong in his interpretation of this authority is completely unsustainable.’

Bezeliansky confirmed that Thwaite not only provides authority for a court to opt to refuse to enforce an executory order, i.e. that it acts as a ‘shield’, but also extended to being able to set aside or vary the order and hence permits the substantive amendment of an executory order, i.e. it acts as a ‘sword’. As Poole J observed in Collardeau v Fuchs:

‘42 In Bezelianksi v Bezelianskaya [2016] EWCA Civ 76, a refusal of permission to appeal and thus not strictly binding on this Court,[[1]] the Court of Appeal made it very clear that the Thwaite jurisdiction as it is sometimes called, exists.’

Bezeliansky was therefore the first time this power was confirmed after argument on the point (albeit where only one party was represented by counsel). However, as noted above, the case shared with Thwaite the three similarities as set out above. This is of importance given that when the Court of Appeal approved Moor J’s decision to vary the order (rather than simply to refuse to enforce it) it did so having emphasised at [36] the point in Thwaite as set out above that the court’s jurisdiction arose ‘from the fact that the wife’s original application for ancillary relief was still before the court and awaiting adjudication. It had not been dismissed … that part of the order … by which her application was dismissed, had never come into effect’.

Bezeliansky does not therefore seek to suggest that the court has any jurisdiction to vary an order where the parties’ claims for financial provision have been dismissed and there is no live application before the court.

The editors of Rayden state at [28.364] that it ‘may be relevant to note’ that in both Thwaite and Bezeliansky the court found that there were other grounds to vary the order. In Thwaite, the judge could have allowed an appeal on the basis of fresh evidence, and in Bezeliansky, a clean break only took place on compliance with other orders.

The views of Mostyn J

Mostyn J first considered the Thwaite jurisdiction in SR v HR (Property Adjustment Orders) [2018] EWHC 606 (Fam), [2018] 2 FLR 843. He stated:

‘9 … it is an iron rule that, aside from a lump sum payable by instalments and aside from a set aside on traditional grounds as discussed below, a capital award cannot be varied, or, a fortiori, discharged, by a court of first instance. That an order has, in the usual way, a “liberty to apply” clause certainly does not entitle a court to rewrite non-variable capital awards and to make different ones. Equally, the fact that a dismissal clause does not take effect until there has been full compliance with certain transfers and payments plainly does not entitle a court to replace an executory order with a new one.’

At [11] and [12] Mostyn J considered the facts of Mullins v Howell (1879) 11 Ch D 763 and Purcell v FC Trigell Ltd [1971] 1 QB 358 and thereafter stated they give ‘no support to the notion that if the court, exercising its equitable jurisdiction, refuses to enforce an order it gains the power to make a completely new one’. He continued:

‘13 I have to say that Mullins v Howell and Purcell v FC Trigell Ltd provide scant support for a loophole to the prohibition of the discharge of a non-variable final capital order. Both cases concerned the court’s power to “control” interlocutory orders. The first case involved an undertaking where there was full power to discharge it anyway. In the second case the court refused to discharge the earlier interlocutory order requiring answers to interrogatories. Therefore, I think that any application under the principle in Thwaite should be approached extremely cautiously and conservatively.’

The editors of Rayden note that it appears that Bezeliansky was not cited to Mostyn J in SR v HR and it is not referred to in his judgment.

Mostyn J returned to the issue in BT v CU [2021] EWFC 87, [2022] 2 FLR 26 from [47]. At [49] and [50] he again considered the facts of Mullins v Howell and Purcell v FC Trigell Ltd and stated both say ‘nothing about the existence of a power to vary a substantive final order which happens to be executory’. Both cases ‘merely say that the court has power to control its interlocutory orders inter alia by not enforcing them’. He continued:

‘51 Thus, Thwaite goes no further than to confirm the existence of an equitable jurisdiction to refuse to enforce an executory order if, in the circumstances prevailing at the time of the application, it would be inequitable to do so. Although the cases relied on by Ormrod LJ relate only to interlocutory orders, he pushed back the boundary of that power so as to cover final orders. But the reasoning in Thwaite does not, on any view, support the idea that there exists some kind of equitable power, not merely to refuse to enforce an executory order, but to make in its stead a completely different one. For this reason, I stated in SR v HR (Property Adjustment Orders) [2018] 2 FLR 843 that any application under the principle in Thwaite should be approached “extremely cautiously and conservatively”, which, of course, was coded language expressing my doubt that the jurisdiction to rewrite (as opposed to mere refusal to enforce) existed at all.’

Thereafter, Mostyn J referred to four authorities which had rejected his doubts as expressed in SR v HR (Property Adjustment Orders) and had held that the court has the power not merely to stay enforcement of an executory order but to rewrite an executory final order to provide for something different to that which it originally stated, namely:

(1) US v SR (No 4) (Executory Mainframe Distribution Order: Change in Circumstances: Extent of the Court’s Ability to Revisit Terms) [2018] EWHC 3207 (Fam) (in which Roberts J pointed out that Thwaite had been followed in L v L – a decision which in turn had referenced Benson v Benson (Deceased) – and Bezeliansky);

(2) Akhmedova v Akhmedov & Ors [2020] EWHC 2235 (Fam), [2021] 1 FLR 667 per Gwynneth Knowles J;

(3) my own decision sitting as a Recorder in G v C [2020] EWFC B35 (OJ); and

(4) Kicinski v Pardi per Lieven J when she allowed the appeal from G v C. In relation to my observation that Bezeliansky was not citable (as it was a decision refusing permission to appeal that had not been certified), Lieven J noted at [29] that the case ‘was a permission to appeal decision and no permission has been given to rely upon it, so far as I am aware’, but stated that ‘it was a fully reasoned decision of three members of the Court of Appeal, including McFarlane LJ (now President of the Family Division). Therefore, although not technically binding on me, it carries the very greatest weight’.

At [63] of BT v CU Mostyn J stated that he did not agree with these four decisions as they appeared to be in conflict with the binding precedent of Barder (and he noted at [46] that in Barder itself the order under appeal was executory yet, fully aware of Thwaite, the House of Lords did not decide the case by reference to that doctrine and therefore ‘must be taken as having impliedly rejected this route as a legitimate source of relief’).

When considering Matrimonial Causes Act 1973, s 31, Mostyn J stated as follows:

‘64 There is nothing within the terms of s31 of the Matrimonial Causes Act 1973 to suggest that its strict curtailment of the power of variation and discharge is confined only to orders which have been performed. An application to set aside an executory order under the Barder doctrine is explicable as an exercise of appellate powers, now replaced by a specific rule permitting the power to be exercised at first instance. An application to set aside an executory order based on fraud, or mistake, can be explained as a separate cause of action. These are surely the only legitimate exceptions to the statutory prohibition on variation of the amount of capital settlements.

65 In the nature of things the variation powers in s31 will apply predominantly to unexecuted orders. Some are variable; most are not. It is a carefully devised scheme which was proposed by the Law Commission (see below) and democratically enacted by Parliament. The Thwaite exception, as developed in L v L and the later cases, in my opinion drives a coach and horses through the statutory scheme.

66 If this route were available, then it means that many Barder cases, including Barder itself, will have been tried, and in most cases dismissed, applying a set of principles far more rigorous than those required under the executory order doctrine. This is because most Barder cases, including Barder itself, concern orders which are executory. It would therefore seem, if the proponents of the executory order doctrine are correct, that the entire litigation in Barder itself, all the way to the House of Lords, was conducted on a completely wrong footing.’

Sir Nicholas Mostyn’s views have not altered since his retirement from the Bench. When posting on LinkedIn in relation to the recent Court of Appeal decision in De La Sala & Anor v De La Sala & Ors [2026] EWCA Civ 282 (17 March 2026), Sir Nicholas Mostyn stated that ‘Pedantic lawyers can be grateful that the completely spurious Thwaite jurisdiction was not invoked to seek to set aside the order’.

Dealing with the differing judicial approaches

It is of note that in Collardeau v Fuchs Poole J stated at [43]:

‘43 Mr. Chamberlayne did not seek to rely on Mostyn J’s judgment in BT v CU [2022] 2 FLR 26 in which he asserted that Thwaite did not support the idea that there was an equitable power to vary an executory order by making “a completely different one.”’

In H v W [2023] EWFC 120 (B) (a decision which is not formally citable and so not capable of being referred to as primary authority but which has been referred to on many occasions since its publication), HHJ Reardon observed:

‘52 Mostyn J’s conclusion, in essence, was that where the court is dealing with an unexpected change in circumstances since the order was made, the stringent test in Barder should not be replaced by a different, potentially less stringent test, simply because the order is still executory.’

HHJ Reardon noted, however, that one significant difference between BT v CU and the cases in which the Thwaite jurisdiction has been exercised was that for the most part the latter cases involve circumstances where there has been an element of deliberate frustration of the implementation of an unexecuted order. Therefore she stated at [53] that ‘one answer to Mostyn J’s argument in BT is that many “deliberate frustration” cases might well fail the first limb of Barder on the basis that the events in question were foreseeable, especially if the responsible party has a history of obstructive behaviour’ and at [54] that ‘[i]t would be strange if the Family Court offered no remedy for the disadvantaged spouse in cases in that category’. She continued:

‘During the course of submissions I asked Mr Tait, for W, what other remedy would be available where, prior to implementation, one spouse has culpably and foreseeably reduced the value of an asset that is within their control but is due to pass to the other spouse on implementation. Mr Tait suggested that if an undertaking has been given, the other spouse could apply for committal for breach; or that, if the asset in question is real property, there might be a remedy in a different court under TLATA 1996. But those remedies are cumbersome and uncertain (committal does not of course provide a financial remedy at all), and their availability is contingent on the nature of the asset and the terms of the order.’

This led HHJ Reardon to conclude as follows:

‘56 … in the Thwaite cases (particularly Bezeliansky, the facts of which are similar to the facts of the present case, albeit played out on a bigger stage) there is usually a close link between the executory nature of the order and the disaffected spouse’s ability to frustrate it. This is particularly obvious in property sale or transfer cases, where, however tightly-drafted the order, the owner of the property is likely to have a number of opportunities to obstruct and delay the sale or transfer, or otherwise to diminish the value of the asset, in the pre-implementation period. The Thwaite jurisdiction would appear to be the only remedy available in such cases, where the change in circumstance has brought about a foreseeably disaffected spouse, rather than an unforeseeable event.

57 For these reasons it is my view that the Thwaite jurisdiction does exist as a separate remedy to Barder. I would suggest that its use may be particularly apt where:

a. The respondent has culpably acted in such a way as to diminish the value of an asset, or otherwise to frustrate the intention behind the order;

b. There is a link between the executory nature of the order and the change in circumstances: ie, it is the fact that the order remains executory that has provided the respondent with the opportunity to frustrate it; and

c. The applicant might well fail the first limb of the Barder test because the respondent’s conduct was foreseeable.’

In L v O (Stay of Order; Hadkinson Order; Security for Costs) [2024] EWFC 6, [2024] 2 FLR 343 Cobb J (as he then was), having referred at [2] to BT v CU noted that ‘[t]he Thwaite jurisdiction (which is less stringent than Barder) is not uncontroversial’.

The existence (or otherwise) of the Thwaite jurisdiction was next considered in WZ v HZ [2024] EWFC 407 (B) per District Judge Doman. Although this decision is also not formally citeable it is another useful example of the exercise of the discretion. At [55] he cited from Bezeliansky and stated ‘[c]learly, ratio from the Court of Appeal is binding authority on me’. In this particular context this appears not to have been correct given that Bezeliansky is not formally citable. Thereafter at [143] the judge stated ‘[t]he Wife in her submissions seeks to persuade me that the Thwaite jurisdiction is highly controversial. It is only really Mostyn J that has expressed such a view. In H v W HHJ Reardon deals with the suggestion that this is a “rare jurisdiction”, note, not controversial at [56] and [57] of her judgment’ before citing further from H v W and also AFW v RFH.

District Judge Doman therefore varied the terms of an order for sale where the wife refused to cooperate with the sale of the former matrimonial home (of which she was to receive the entirety of the proceeds and where an offer had been made far in excess of the value used at final hearing). He concluded at [149] that ‘[a]s £675,000 would meet the Wife’s need and she has been the one to frustrate the order it seems fair to me that the Thwaite jurisdiction should be invoked to ensure that any monies over £675,000 be paid to the Husband’.

In Hersman v De Verchere [2024] EWHC 905 (Fam), [2024] 2 FLR 1011 Moor J at [28] stated he had ‘no doubt whatsoever’ that the court had jurisdiction to make orders ‘working out and enforcing’ earlier financial remedy orders as ‘[i]t would be a very surprising and unjust omission if such a power did not exist. It would be a cheats charter and encourage non-compliance or obstruction with legitimate court orders’. He cited Bezeliansky per McFarlane LJ (as he then was) at [37] as confirming that that the jurisdiction exists to enable a judge to make such orders where the order remains ‘executory’.

It is important to consider whether Hersman v De Verchere was in fact an exercise of the Thwaite jurisdiction. It was an enforcement application after the wife had failed to transfer a ski chalet to the husband pursuant to a final order and the husband sought substantial sums by way of compensation (primarily in the form of lost rental income and mortgage interest/penalties). Further, query whether Thwaite is as Moor J stated in fact synonymous with the court’s jurisdiction ‘working out and enforcing’ earlier orders and whether this is more properly the realm of the liberty to apply and the enforcement jurisdiction.

The views of Peel J

In Rotenberg v Rotenberg & Ors [2024] EWFC 185, [2025] 1 FLR 351 Peel J stated:

‘55 … I do not propose to traverse the Thwaite jurisdiction which has been set out comprehensively by leading counsel for H. Although doubt has been expressed by Mostyn J as to the existence of the Thwaite jurisdiction in SR v HR [2018] EWHC 606 (Fam), I have not heard argument on the point and am inclined to accept, for the purposes of this case, that the jurisdiction does indeed exist, although it should be used sparingly. The essence of the jurisdiction is that the court may adjust an executory order (i.e. before it has been complied with) if it would be inequitable not to do so, most commonly where there has been a significant and necessarily relevant change of circumstances since the order was made.’

In Rotenberg, within Matrimonial and Family Proceedings Act 1984, Part III proceedings, Moor J had ordered that a company, Ravendark Holdings Limited, was to transfer a property to the wife to provide a home for her and the children in England. However, the wife left for Russia 2 years later and did not return. The husband applied (at [29]) ‘purportedly under the Thwaite jurisdiction for “a stay preventing the execution of, and permanently suspending the implementation of the order of Mr Justice Moor dated 20 July 2016”’ on grounds that there had been a significant change of circumstances since the order was made (i.e. the wife had, contrary to her evidence, left the jurisdiction with the parties’ two children to live overseas).

Peel J exercised the Thwaite jurisdiction although he did so by discharging the applicable paragraphs of the Part III order in their entirety. He noted at [57 (v)] that ‘in my judgment, the landscape on the ground was very different from that which was envisaged at the time of the order made on 20 July 2016. The facts of this case are exceptional, and justify the order being reframed’.

It has been said that: (1) Rotenberg is further authority for the proposition that the Thwaite jurisdiction can be used proactively as the basis for an application (a sword) rather than merely in response to an application to enforce (a shield); and (2) Peel J discharged provisions of the 2016 and 2019 orders and did so regardless of (and in full knowledge of) Mostyn J’s two judgments in SR v HR and BT v CU.

However, there may be some reason to be cautious that Rotenberg is further authority for such a proposition. The successful application was narrow – H sought an indefinite stay of certain provisions of Moor J’s order and ultimately achieved their discharge. It is therefore arguable that this is in keeping with the original ambit of Thwaite – namely prevention of enforcement/implementation rather than a wholesale rewrite/variation – and is therefore an example of the jurisdiction being exercised in its uncontroversial ‘shield’ sense.

Rotenberg may also be said to be important given that Peel J’s decision to exercise the Thwaite jurisdiction did not depend on a finding that there had been a deliberate frustration of the implementation of an executory order, which was the theory contemplated by HHJ Reardon in H v W. It may be of note in this context, however, that: (1) although Peel J stated (at [57 (iii)]) that the court was prima facie misled in 2019 when the husband had made his original application (Moor J accepted that the wife had intended to return to England when instead she and the children had moved abroad and had not been back since 2018); (2) he also said that even if Moor J was not misled ‘there has been a material change in circumstances since the 2016 and 2019 orders … That undermines the essential basis upon which the order was made …’. In other words, it may be said that Peel J’s order did not depend on a finding that the court was misled and he was able to revisit the order simply because it remained executory.

Further, there are additional reasons to be cautious in how far forward Rotenberg takes the debate in relation to the existence and scope of this jurisdiction given: (1) Peel J was clear he had not heard argument in respect of the Thwaite jurisdiction (and in particular on BT v CU and – in Mostyn J’s view – the irreconcilable tensions between Thwaite and Barder); and (2) he was also merely ‘inclined to accept for the purposes of this case’ that the jurisdiction existed.

Further differing judicial approaches

In AP v TP (Pension Enforcement) [2025] EWFC 190 (B) (again not formally citable but another interesting exercise of the jurisdiction), HHJ Farquhar from [24] onwards referred to and/or cited from Thwaite, WZ v HZ and Bezeliansky before stating at [27] ‘there has been considerable debate as to the extent and indeed the availability of the Thwaite jurisdiction’ and citing from BT v CU per Mostyn J. At [28] he then stated that Mostyn J’s view was ‘in stark contrast’ to the position in Hersman v De Verchere per Moor J and at [29] that in Rotenberg v Rotenberg Peel J ‘was satisfied that the Thwaite jurisdiction was still good law’. Thereafter, he stated as follows:

‘30 I have been referred to the analysis of the Thwaite Jurisdiction of HHJ Reardon in H v W [2023] EWFC 120 at paragraphs 46 to 59 in which she refers to a number of the authorities that I have set out above. I find myself in full agreement with the decision of HHJ Reardon which I do not set out in full but summarise as follows:

a. It would be strange if the Family Court offered no remedy for the disadvantaged spouse in cases in which the other spouse had deliberately frustrated the order.

b. The essence of Thwaite is fairness.

c. However, in exercising the jurisdiction the court is not approaching the situation with fresh eyes. Thwaite itself, Bezeliansky and L v L [2008] 1 FLR 13 all refer to making an adjustment from the terms of the final order not because it is fair to do so, but because in the light of events since the order it would be inequitable not to do so.’

HHJ Farquhar therefore exercised the jurisdiction so as to set aside a pension sharing order that had been made in the wife’s favour after she refused to cooperate with its implementation and the husband could not retire without access to the pension funds.

In M v B [2025] EWFC 182, [2026] 1 FLR 194, Sir Jonathan Cohen considered a strike out of a Thwaite application. The case considered the jurisdiction to strike out an application on a summary basis (a question considered in Roocroft v Ball [2016] EWCA Civ 1009, [2017] 2 FLR 810 (which in turn considered Vince v Wyatt [2015] UKSC 14, [2015] 1 FLR 972), AB v CD [2022] EWFC 116 and Ma v Roux [2024] EWHC 1917 (Fam)). As a result, the correctness (or otherwise) of the Thwaite jurisdiction was expressly not in issue:

‘13 W expressly parked her argument over the continued controversy in family law circles as to whether Thwaite does in fact present a freestanding jurisdiction to set aside and vary an executory order. Mr Dance on her behalf accepted that a strike out application was not the time to seek a judgment determining that controversy. …

16 It is not necessary in this judgment to enter into the debate over the existence of a Thwaite jurisdiction and whether it establishes that a lower threshold than a Barder event suffices to give the court jurisdiction to vary an order which is executory. Neither is it necessary at this stage for the court to determine whether or not an absence of fault on the part of the party seeking to enforce is fatal to an application to vary made by the party in default.’

In X v Y [2025] EWFC 144 (B) (again not formally citable but a very detailed analysis of the jurisdiction), District Judge Stone stated:

‘28 It is the existence (or otherwise) and the extent of the Thwaite jurisdiction that requires exploration. Specifically there are 3 questions I must answer to establish a legal framework to which I can then apply the facts of this particular case:

a. What are the conditions that must be fulfilled to rely upon the Thwaite jurisdiction?

b. What does it enable the court to do?

c. Does the jurisdiction even exist – ie has it survived Barder?’

The District Judge continued:

‘30 This judgment is not intended to be a treatise on the Thwaite jurisdiction – I leave that to many more qualified than I am. However, the authorities and commentaries are inconsistent and it is difficult to pin down the existence and extent of the Thwaite jurisdiction without methodically reviewing the authorities, so needs must.’

X v Y concerned a party’s application to vary an order which set out how the proceeds of sale of a property should be divided. An order for sale was made at the final hearing and by the date of the application to set aside and/or vary the order the property had not sold and the estate agents were recommending a further reduction in the marketing price.

From [31]–[69] there followed a detailed analysis of Thwaite, Bezeliansky, L v L, US v SR, BT v CU and Kicinski v Pardi that justifies careful reading. Thereafter, the District Judge answered the three questions he posed at [28] of his judgment in the following way:

‘70 The resulting position appears not to have moved on greatly from Thwaite itself.

a. What are the conditions that must be fulfilled to rely upon the Thwaite jurisdiction?

There must have been a change of circumstances that would render it inequitable to hold one party to the financial provision order that has not yet been implemented (ie is executory). By definition a minor change in circumstances would not be sufficient to render it inequitable to hold a party to it, so it is inherent that the change of circumstances must be significant. Where the change of circumstances has been brought about by the other party’s inappropriate conduct, that also may point towards inequitability.

It is not necessary for the change to be unforeseeable. Indeed, in some cases where a party has conducted themselves badly throughout the process, an attempt to frustrate the implementation of an order may be as foreseeable as it is inequitable.

b. What does it enable the court to do?’

It enables a court to refuse to enforce the relevant provision of the order if to do so would be inequitable.

Whilst some of the High Court decisions appear to conflate the issues of refusal to enforce with an ability to alter the order, the basis for asserting that the court has a general jurisdiction to alter the order is unclear. It appears to arise from the fact that in Thwaite the court did vary the order, but it did so only because the parties’ claims remained live before the court and had not been dismissed.

c. Does the jurisdiction exist – ie has it survived Barder?

Despite the best efforts of Mostyn J to interpret the House of Lords’ silence regarding Thwaite in the subsequent Barder judgment, there is no doubt that the jurisdiction continues to exist. If it had not survived the Court of Appeal would not have referred to it in the Bezeliansky permission to appeal decision.’

This therefore led the judge to the following conclusion:

‘71 If my analysis above is correct, then were I to conclude that a reduction in the value of the family home was a sufficiently significant change to render it inequitable to hold Mr X to the current order, I could refuse to enforce that part of the order. I would nevertheless have no jurisdiction then to vary the order.

72 The reason is straightforward: Mrs Y’s capital claims and Mr X’s capital and periodical payments claims have been dismissed. The dismissal of those claims was not conditional upon the implementation of the property transfer: it was immediate. Accordingly the conditions in Thwaite that enabled the court to vary the order (from the fact that the wife’s original application for ancillary relief was still before the court and awaiting adjudication – it had not been dismissed since the conveyance had never been executed) do not exist here. The parties’ claims have been dismissed and are not live before the court, such that there is no ongoing jurisdiction to determine them.’

The husband’s application to vary the capital provision contained in the order (how the net proceeds of sale of a property were to be divided) was therefore dismissed. The judge stated, however, at [73] that in the event that he was wrong and that he did have the jurisdiction to make the order sought, he did not consider that the reduction in value of the property was a sufficiently significant change to render it unfair to hold the husband to it.

The District Judge therefore concluded that the Thwaite jurisdiction survives as a ‘shield’ to enforcement of the relevant provision of the order if there has been a change of circumstances that would render it inequitable to do otherwise. However, the basis for asserting that the court has a general jurisdiction to alter the order remained unclear and appeared to arise from the fact that in Thwaite the court varied the order only because the parties’ claims remained live before the court and had not been dismissed. The position was the same in Bezeliansky as there was still a live application before the court to be determined because, as in Thwaite, the conditions that would dismiss the parties’ claims for financial provision had not been fulfilled. Bezeliansky it was said does not therefore seek to suggest that the court has any jurisdiction to vary an order where the parties’ claims for financial provision have been dismissed and there is no live application before the court.

In Collardeau v Fuchs, Poole J observed:

‘45 Here, the Final Order is executory and there have been a number of changes in circumstances since the order was made, most importantly the failure of H to abide by his undertakings and the impending loss of the family home.’

Poole J then went on to make a number of orders that varied the terms of the original final order.

So where are we now?

Does the above mean that Mostyn J and District Judge Stone are lone voices or dissenters and that as a remedy Thwaite remains viable and available to the extent that an order remains executory and there has been a material change in circumstances since the order was made such that it would be inequitable not to vary the same? Can it therefore properly be used as a ‘sword’ rather than simply a ‘shield’? If so, does that require a party’s (or the parties’) claims to remain live and before the court? Is there good reason to conclude that the new circumstances (or event) that justify a variation do not need to be unforeseen in circumstances where there has been non-compliance by a respondent and/or they have culpably acted to frustrate the intention behind the order?

It may be difficult (if not impossible) to answer these questions given the – arguably – contradictory authorities.

However, notwithstanding this there may be one way to reconcile the same – or at least largely seek to do so.

It may be argued that Mostyn J’s analysis of the proper scope of the Thwaite jurisdiction is correct (i.e. that it exists solely as a ‘shield’ to enforcement) but that notwithstanding the restrictions imposed by MCA 1973, s 31 there is also the need for a remedy for the reasons advanced by Moor J, HHJ Reardon, District Judge Doman and HHJ Farquhar.

If so, the correct position in law would be as follows:

(1) Barder confirms the availability of a set-aside jurisdiction if the requisite criteria are satisfied (which include unforseeability);

(2) Thwaite confirms the availability of an equitable jurisdiction to refuse to enforce an executory order if, in the circumstances prevailing at the time of the application, it would be inequitable to do so;

(3) save for (4) below the court may only vary what would otherwise be a non-variable order that remains executory if one party’s (or both parties’) application(s) for financial orders has (or have) not yet been dismissed (although Mostyn J is clear in his view that the fact that a dismissal clause does not take effect until there has been full compliance with certain transfers and payments does not entitle a court to replace an executory order with a new one); and

(4) there is (or at least there should also be) an equitable jurisdiction to vary an executory order in circumstances where there has been non-compliance by a respondent and/or they have culpably acted to frustrate the intention behind the order. These circumstances do not need to have been unforeseen.

The argument would be that this latter equitable jurisdiction is required as, otherwise (as Moor J observed in Hersman v De Verchere), it would be a cheat’s charter and encourage non-compliance or obstruction with legitimate court orders where claims had otherwise been dismissed. It would be said that this is the power exercised in H v W by HHJ Reardon, in WZ v HZ by District Judge Doman, and in AP v TP by HHJ Farquhar.

It may be argued that this was the jurisdiction exercised by Poole J in Collardeau v Fuchs – as the husband was the non-compliant party and had failed to abide by his undertakings – when at [52] the judge stated he had jurisdiction to discharge an undertaking to pay the future monthly mortgage on a property and to order that the husband pay the wife a lump sum award which was the capital equivalent of the periodical payments that the husband had undertaken to pay – although Poole J considered this to be a power he had under the Thwaite jurisdiction but also (as he said at [45]) under MCA 1973, s 31.

The contrary argument would be that such a capitalisation order could only be made pursuant to the Thwaite jurisdiction being used as a ‘sword’ given that it related to an undertaking. In L v L, Munby J (as he then was) expressed the view at [100] that ‘the court can perfectly properly accept undertakings which impose obligations that the court could not itself impose, and such undertakings are nonetheless just as enforceable as an order of the court’ and at [113] that:

‘[s]ection 31 of the 1973 Act entitles the husband to apply for an order varying, discharging or suspending that part of the consent order which constitutes an order for periodical payments. That entitlement is not in any way affected either by the fact that the order was a consent order or by the fact that the relevant provisions are contained in undertakings rather than in the curial part of the order.’

However, in Birch v Birch [2017] UKSC 53, [2017] 2 FLR 1031, Lord Wilson took a more restrictive view of the court’s powers to ‘vary’ an undertaking (whether under s 31 or otherwise) in the following terms:

‘5 All three lower courts adopted without demur the wife’s description of her application as being to “vary” her undertaking. But her description betrays a conceptual confusion which it is as well to dispel as this early stage. An undertaking is a solemn promise which a litigant volunteers to the court. A court has no power to impose any variation of the terms of a voluntary promise. A litigant who wishes to cease to be bound by her (or his) undertaking should apply for “release” from it (or “discharge” of it); and often she will accompany her application for release with an offer of a further undertaking in different terms. The court may decide to accept the further undertaking and, in the light of it, to grant the application for release. Equally, the court may indicate that it will grant the application for release only on condition that she is willing to give a further undertaking or one in terms different from those of a further undertaking currently on offer. In either event the court’s power is only to grant or refuse the application for release; and, although exercise of its power may result in something which looks like a variation of an undertaking, it is the product of a different process of reasoning.’

Acknowledging the existence of a freestanding equitable jurisdiction would also be consistent with the observation in Bezeliansky per McFarlane LJ (as he then was) at [39] that ‘the circumstances justifying intervention are likely to be met where an order remains executory as a result of one party frustrating its implementation’ (emphasis added). Such an analysis would therefore reflect the only Court of Appeal decision on this issue.

However, it would arguably be inaccurate to call this an exercise of the Thwaite jurisdiction as it is not, for the reasons espoused in BT v CU including that Thwaite is simply a ‘shield’ jurisdiction – and which is why the House of Lords in Barder did not decide the case by reference to it.

The contrary argument would be that although it may be said there should be such a jurisdiction, there is not one and one cannot be created by common law in the face of MCA 1973, s 31 and hence offends against the boundaries of statutory construction and that this lacuna can only be resolved by statutory reform. This is why, in Mostyn J’s opinion, as stated in BT v CU at [65], the Thwaite jurisdiction ‘drives a coach and horses through the statutory scheme’.

It is likely that only consideration of the above issues by the Court of Appeal – after hearing full argument – will (finally) determine the question of the ongoing existence of the Thwaite jurisdiction and, if it does still exist, its appropriate scope.

So the jury is still out. Whether the Court of Appeal will deliver a unanimous or majority verdict in due course remains to be seen.

[[1]]: A decision refusing permission to appeal that had not been certified cannot be relied upon as authority (Practice Direction (Citation of Authorities) [2001] 1 WLR 1001 at para 6.2 and FPR PD 27A, para 4.3A.2.