Introduction

The enforcement of foreign judgments in England and Wales is a matter of considerable practical significance in cross-border commercial and civil litigation. When the judgment in question emanates from the United States, the applicable enforcement framework is exclusively the common law regime. The United States is not a party to the statutory schemes under the Administration of Justice Act 1920 or the Foreign Judgments (Reciprocal Enforcement) Act 1933, nor is it presently a contracting state to the Hague Convention on the Recognition and Enforcement of Foreign Judgments in Civil or Commercial Matters 2019, which entered into force in the United Kingdom on 1 July 2025.[1]

The theoretical foundation for enforcement at common law is the doctrine of obligation: where a court of competent jurisdiction has adjudicated that a definite sum is due from one person to another, a legal obligation arises to pay that sum, upon which an action of debt may be maintained in England.[2] This obligation exists independently of reciprocity or comity; the English court does not inquire into whether English judgments would be enforced in the foreign jurisdiction.[3]

The position is complicated, however, by the Protection of Trading Interests Act 1980 (“PTIA 1980”), a statute enacted in response to what the United Kingdom perceived as an excessive assertion of extraterritorial jurisdiction by United States courts, particularly in antitrust proceedings. Section 5 of the PTIA 1980 imposes an absolute prohibition on the enforcement of foreign judgments for “multiple damages,” a provision whose scope and severity have been the subject of significant recent appellate consideration. This article examines the common law requirements for the enforcement of US judgments, analyses the effect of the PTIA 1980, and considers the practical consequences of the Court of Appeal’s landmark decision in Motorola Solutions Inc v Hytera Communications Corp Ltd [2025] EWCA Civ 1667.

The Common Law Requirements for Enforcement

The Prerequisites

Dicey, Morris & Collins’ Rule 46 restates the common law position: a foreign judgment in personam must satisfy four cumulative conditions to be enforceable by way of a fresh action in England.[4] First, the judgment must be for a debt or definite sum of money, excluding sums payable in respect of taxes, fines, or other penalties. Secondly, the judgment must be final and conclusive in the court which pronounced it. Thirdly, the original court must have had jurisdiction to give the judgment in accordance with the principles of English private international law. Fourthly, the judgment must not be impeachable on any of the recognised grounds of defence.

The requirement of finality merits particular attention in the context of US judgments. A judgment is final and conclusive if the court that rendered it treated the determination as a res judicata, conclusively and forever establishing the existence of the debt as between the parties.[5] Critically, the test of finality refers to the treatment of the judgment by the court that pronounced it—not its status within the broader court system. The judgment of a court of a single American state is assessed for finality solely by reference to the law of that state; its finality or conclusiveness in other states of the Union is irrelevant.[6]

The fact that a judgment is subject to appeal, or that an appeal is actually pending, does not deprive it of its final character.[7] This principle is of considerable practical importance in the US context, where appellate processes may be protracted. The judgment must also have been given “on the merits”: a decision which establishes certain facts as proved, identifies the relevant principles of law, and expresses a conclusion as to the effect of applying those principles to the facts.[8] A default judgment may be final and conclusive in this sense, even though it is liable to be set aside by the court which rendered it, provided that it is given the effect of finality unless subsequently altered.

Jurisdictional Requirements

The most analytically demanding element of the common law framework is the requirement that the foreign court possessed jurisdiction according to English conflict of laws rules. English law applies its own principles to determine whether the foreign court had a recognised basis for exercising jurisdiction; it does not defer to the foreign court’s own assessment of its competence.[9] The two principal bases are territorial presence (or residence) and submission.[10]

Regarding natural persons, presence in the foreign country at the date when proceedings were commenced is sufficient. For corporations, the test established in Adams v Cape Industries Plc requires that the corporation had established and maintained a fixed place of business in the foreign jurisdiction at which it carried on its own business for more than a minimal period, or that a representative was carrying on the corporation’s business from such a fixed place. Where a subsidiary is alleged to constitute the parent’s presence, the court must examine whether the subsidiary acted as agent and, if so, on what terms.[11]

Submission as a basis of jurisdiction encompasses the defendant’s selection of the forum as plaintiff, voluntary appearance in the proceedings, and contractual agreement to submit.[12] In Rubin v Eurofinance SA, the Supreme Court restated that characterisation of submission depends on English law, and that the foreign court’s own assessment is not determinative.[13] The question is to be inferred from all the facts, with the court applying a “broader approach” which looks beyond the specific procedural step taken.[14] A defendant who contests the jurisdiction of the foreign court does not thereby submit to it, provided the steps taken do not extend beyond what is necessary to challenge jurisdiction—even where the foreign procedural rules require the jurisdictional challenge and the merits defence to be advanced simultaneously.[15]

The submission question is frequently the most vigorously contested issue in enforcement proceedings relating to US judgments, particularly where a defendant domiciled in England engaged with the US proceedings to a limited extent—perhaps by corresponding with the court or attending a preliminary hearing—without intending to submit. The critical distinction is between engaging substantively with the merits of the claim (which may constitute submission) and merely protesting the court’s jurisdiction (which does not).[16]

Defences

Even where the jurisdictional and formal requirements are met, a foreign judgment may be impeached on recognised grounds: fraud on the part of the judgment creditor; that enforcement would be contrary to English public policy; and that the proceedings were conducted in breach of natural justice.[17] The fraud defence is of particular note: English law permits a defendant to raise fraud as a ground for resisting enforcement even where the allegation was, or could have been, adjudicated upon in the foreign proceedings.[18] A further ground of defence, specific to certain US judgments, arises under the PTIA 1980.

The Protection of Trading Interests Act 1980

Legislative Purpose and Section 5

The PTIA 1980 was enacted to provide protection against requirements, prohibitions, and judgments imposed under the laws of countries outside the United Kingdom that affect the trading or other interests of persons in this country.[19] Its most consequential provision for enforcement purposes is section 5, which provides that a qualifying judgment “shall not be registered” under the statutory enforcement regimes and that “no court in the United Kingdom shall entertain proceedings at common law for the recovery of any sum payable under such a judgment.”[20]

The qualifying judgments to which section 5 applies are: (a) a judgment for multiple damages, defined as a judgment for an amount arrived at by doubling, trebling, or otherwise multiplying a sum assessed as compensation;[21] (b) a judgment based on a provision or rule of law specified by the Secretary of State as concerned with the prohibition or regulation of restrictive trade practices;[22] and (c) a judgment on a claim for contribution in respect of damages falling within either foregoing category. The principal target was the treble damages remedy available under US antitrust legislation, but the provision applies to judgments of all overseas countries and extends beyond the antitrust context to any judgment arrived at by a process of multiplication.[23]

Motorola v Hytera: The Scope of the Prohibition

The central interpretive question under section 5 was whether the prohibition extends only to the punitive or multiplicative element of a damages award, or whether it renders the entire judgment—including the compensatory component—unenforceable. This question was authoritatively resolved by the Court of Appeal in Motorola Solutions Inc v Hytera Communications Corp Ltd.[24]

Motorola had obtained judgment in the US District Court for the Northern District of Illinois for intellectual property misappropriation under the Defend Trade Secrets Act (“DTSA”), which permits the award of punitive damages of up to twice the compensatory sum for wilful and malicious breaches. The question before the Court of Appeal was whether section 5 prohibited enforcement of only the additional punitive element, or the entire award including the compensatory damages that had been multiplied to reach the total figure. The Court held that the statutory language was “clear and unambiguous” in barring enforcement of the whole of a multiple damages claim, including its compensatory part.[25]

The reasoning turned on the statutory language of section 5(3). A judgment for multiple damages means one for “an amount arrived at by doubling, trebling or otherwise multiplying a sum assessed as compensation.” Where, for example, a judgment of US$3,000 is calculated by trebling a compensatory award of US$1,000, the entirety of the US$3,000 constitutes the “amount arrived at” by the process of multiplication; the “amount arrived at” is not merely the additional US$2,000 representing the punitive element. This reasoning departed from the earlier obiter analysis of Mann J in Lucasfilm, who had expressed the view that removing the compensatory element would itself amount to a penalty requiring clearer statutory language.[26] The Court of Appeal disagreed, holding that the statutory wording was sufficiently clear and that the purpose of section 5 extended beyond mere disapproval of the multiple damages concept to encompass a broader policy: English courts should not lend any assistance to the enforcement of judgments whose nature involves the multiplication of compensation.[27] The rationale was analogised to the longstanding prohibition on the enforcement of foreign penal laws.[28]

Severability: A Critical Distinction

The absolute prohibition does not, however, preclude enforcement of separate, non-multiplied causes of action within the same proceedings. The principle of severability operates where a foreign court has given judgment in respect of several distinct causes of action, only some of which involve the multiplication of damages. In Pace Europe Ltd v Dunham,[29] the court enforced a compensatory award arising from common law causes of action notwithstanding that a separate element of the same judgment comprised multiple damages under a statutory unfair and deceptive practices claim. The critical distinction—reinforced by the Court of Appeal in Lewis v Eliades and SAS Institute—is between a judgment for multiple damages on a particular cause of action and a judgment which happens to include both multiplied and non-multiplied awards on separate causes of action.[30]

The practical implications of this distinction are significant. Where a US judgment encompasses both statutory claims carrying multiple damages and distinct common law claims attracting only compensatory damages, an enforcement claimant may sever the latter from the former and enforce them in England. But where the multiplied and compensatory elements derive from the same cause of action, no severability is available and the entire award under that cause of action is lost. In Khan v David, the court considered the related question of whether a compensatory award was “contaminated” by association with a punitive damages judgment, holding that there was a good arguable case that the compensatory award was not barred where the orders did not themselves involve a process of multiplication applied to a compensation sum.[31]

Section 6: The Claw-Back Remedy

Section 6 of the PTIA 1980 provides a further, offensive remedy. Where a court of an overseas country has given a judgment for multiple damages against a qualifying defendant—a UK citizen, a body corporate incorporated in the United Kingdom, or a person carrying on business here—and the defendant has paid an amount on account of those damages, the defendant is entitled to recover so much of the amount paid as exceeds the compensatory element.[32] The claw-back right is subject to exceptions: it does not apply where the qualifying defendant was ordinarily resident in the overseas country when proceedings were instituted, or where the defendant’s business in the overseas country was the exclusive subject of the proceedings.[33]

The practical utility of section 6 depends upon the judgment creditor having assets within the United Kingdom or in a jurisdiction that will recognise the English claw-back judgment.[34] The section contains the notable provision that proceedings may be brought notwithstanding that the plaintiff in the foreign proceedings is not within the jurisdiction of the UK court, with no requirement for permission to serve out—a deliberate assertion of extraterritorial reach that mirrors, in a sense, the very jurisdictional approach the Act was designed to counteract.

Practical Considerations

The combined effect of the common law framework and the PTIA 1980 creates a landscape in which the enforcement of US judgments requires careful preliminary analysis. Several practical considerations arise for the enforcement practitioner.

Structure of the US award. The enforceability analysis must begin with a granular examination of the US judgment itself. Where the judgment encompasses multiple causes of action, the practitioner must identify whether any involve the multiplication of a compensatory sum. If multiple damages have been awarded on one cause of action but purely compensatory damages on another, the case for severability is strong. If, however, the entire quantum has been arrived at through a process of multiplication applied to a single assessed compensation figure, Motorola renders the whole award under that cause of action unenforceable.

Ancillary relief. Calver J held at first instance in Motorola that awards of interest, costs, and disbursements ancillary to a judgment for multiple damages were themselves unenforceable under section 5 where the US court had awarded those sums in respect of the action as a whole and apportionment was not possible.[35] Practitioners must therefore consider whether ancillary elements of the US judgment can be disaggregated from the multiplied component.

Stays pending foreign appeals. The Court of Appeal in Motorola addressed the court’s power to manage the situation where a foreign judgment, having been enforced in England, is subsequently overturned abroad. The Court preferred the use of stays under CPR Part 40.8A rather than the repeated revocation and re-entry of final judgments, observing that the private international law framework which permits enforcement of foreign first instance judgments pending appeal necessarily entails the possibility that the English judgment may eventually need to be adjusted.[36] This approach favours stability and finality while preserving the court’s ability to respond to developments in the foreign appellate process.

The Hague Judgments Convention. Looking forward, the entry into force of the 2019 Hague Convention in the UK on 1 July 2025 may over time affect the enforcement landscape.[37] However, its subject matter scope excludes certain categories of claim, including intellectual property, and the United States is not yet a party. For the foreseeable future, US judgments will continue to fall within the common law regime, and the PTIA 1980 will remain a critical feature of the analytical framework.

Conclusion

The enforcement of United States judgments in England and Wales remains governed by the common law regime, which imposes rigorous requirements of finality, monetary character, and jurisdictional competence assessed by English conflict of laws principles. The PTIA 1980 operates as a significant statutory overlay: following Motorola, any judgment for multiple damages is wholly unenforceable, including its compensatory component. The principle of severability offers a partial escape where the US judgment encompasses distinct causes of action, some of which attract only compensatory damages. The claw-back remedy under section 6 affords qualifying defendants an offensive mechanism to recover the punitive element of awards satisfied abroad. Practitioners advising on enforcement must therefore conduct a forensic analysis of the structure of the US award, the basis on which the foreign court assumed jurisdiction, and the precise relationship between any multiplied and non-multiplied elements before commencing proceedings.

 

Disclaimer: This article is provided for general information purposes only and does not constitute legal advice. The law stated is as at March 2026. Specific legal advice should be sought in relation to any particular matter.

Mikhail is a barrister at 5 Pump Court Chambers practising in civil and commercial litigation, with particular experience in the enforcement of foreign judgments and cross-border disputes.

 

[1]Dicey, Morris & Collins on the Conflict of Laws (16th ed., 2022) (“Dicey”), Ch. 14, para. 14-007.

[2]Godard v Gray (1870–1871) LR 6 QB 139; Schibsby v Westenholz (1870) LR 6 QB 155.

[3]Adams v Cape Industries Plc [1990] Ch 433 (CA); Dicey, para. 14-008.

[4]Dicey, para. 14R-024, Rule 46.

[5]Midtown Acquisitions LP v Essar Global Fund Ltd [2017] EWHC 519 (Comm).

[6]Nouvion v Freeman (1889) 15 App Cas 1, 9.

[7]Nouvion v Freeman (1889) 15 App Cas 1, 13; Dicey, para. 14-030.

[8]The Sennar (No. 2) [1985] 1 WLR 490 (HL), per Lord Brandon.

[9]Adams v Cape Industries Plc [1990] Ch 433 (CA), per Slade LJ.

[10]Dicey, paras 14-064 to 14-069.

[12]Emanuel v Symon [1908] 1 KB 302 (CA), per Buckley LJ.

[13]Rubin v Eurofinance SA [2012] UKSC 46, [2013] 1 AC 236, at [161].

[14]ibid. The Supreme Court emphasised that a “broader approach” is necessary, in which the question of submission is to be inferred from all the facts.

[15]Civil Jurisdiction and Judgments Act 1982, s 33; Adams v Cape Industries Plc [1990] Ch 433 (CA).

[16]Rubin v Eurofinance SA [2012] UKSC 46, at [161]. See also Dicey, para. 14-077.

[17]Dicey, paras 14-138 to 14-162.

[18]Abouloff v Oppenheimer (1882) 10 QBD 295 (CA); Owens Bank Ltd v Bracco [1992] 2 AC 443 (HL).

[19]Protection of Trading Interests Act 1980, c 11 (“PTIA 1980”), long title.

[20]PTIA 1980, s 5(1).

[21]PTIA 1980, s 5(3).

[22]PTIA 1980, s 5(2)(b) and s 5(4).

[23]Dicey, para. 14-220; British Airways Board v Laker Airways Ltd [1984] QB 142, 162D–E.

[24]Motorola Solutions Inc v Hytera Communications Corp Ltd [2025] EWCA Civ 1667, at [2].

[25]ibid., at [56].

[26]Lucasfilm Ltd v Ainsworth [2009] EWCA Civ 1328, at [224]–[231], per Mann J at first instance; Pace Europe Ltd v Dunham [2012] EWHC 852 (Ch), per HHJ Purle QC.

[27]Motorola Solutions Inc v Hytera Communications Corp Ltd [2025] EWCA Civ 1667, at [62].

[28]ibid., at [54]. The Court drew an analogy with the prohibition on enforcement of foreign penal laws: British Airways Board v Laker Airways Ltd [1984] QB 142, 163D; Service Temps Inc v MacLeod [2013] CSOH 162, at [35].

[29]Pace Europe Ltd v Dunham [2012] EWHC 852 (Ch).

[30]Lewis v Eliades [2003] EWCA Civ 1758, [2004] 1 WLR 692; SAS Institute Inc v World Programming Ltd [2018] EWHC 3452 (Comm); Dicey, para. 14-221.

[31]Khan v David [2025] EWHC 2611 (KB).

[32]PTIA 1980, s 6(1)–(2).

[33]PTIA 1980, s 6(3)–(4).

[34]Dicey, para. 14-224.

[35]Motorola Solutions Inc v Hytera Communications Corp Ltd [2024] EWHC 2891 (Comm), per Calver J.

[36]Motorola Solutions Inc v Hytera Communications Corp Ltd [2025] EWCA Civ 1667, at [125]–[130].

[37]Hague Convention on the Recognition and Enforcement of Foreign Judgments in Civil or Commercial Matters 2019, entered into force in the UK on 1 July 2025.