Political Change as an Extrinsic Reason for Refusing Costs: Commentary on PCSU v Secretary of State for the Home Department [2025] EWCA Civ 1644

Political Change as an Extrinsic Reason for Refusing Costs: Commentary on Public and Commercial Services Union v Secretary of State for the Home Department [2025] EWCA Civ 1644

1. Introduction

1.1. The case in outline

This Court of Appeal decision concerns not the underlying legality of the Strikes (Minimum Service Levels: Border Security) Regulations 2023/1353 (“the MSL Regulations”), but a narrower – yet practically important – issue: who should pay the costs of judicial review proceedings that become academic because a newly elected government decides, for political reasons, to repeal the challenged legislation and undertakes not to use it in the meantime? The Appellant, the Public and Commercial Services Union (“PCSU”), represents around 185,000 civil service and related workers, including several thousand Border Force staff. It brought a judicial review challenging Regulation 3 of the MSL Regulations, which implemented minimum service levels (“MSLs”) in border security under the Strikes (Minimum Service Levels) Act 2023 (“the 2023 Act”). PCSU’s central substantive contention was that the MSL regime unlawfully interfered with its members’ right to freedom of association under Article 11 of the European Convention on Human Rights (ECHR), including their right to strike, and that Regulation 3 was ultra vires and/or in breach of Article 11. Before those merits could be adjudicated, the political landscape changed: - The Labour Party, which had opposed the 2023 Act while in opposition and had publicly pledged to repeal it, won the July 2024 general election. - The new Minister for Migration and Citizenship wrote to PCSU confirming: - preparations to repeal the 2023 Act via an Employment Rights Bill (with automatic lapsing of all MSL regulations, including those for border security); and - that, pending repeal, the Home Secretary would not exercise powers under the Act or the MSL Regulations. The Government Legal Department (GLD) then argued that the judicial review was now academic and invited PCSU to discontinue without any order for costs in its favour. PCSU discontinued but reserved the right to seek its costs. The Administrative Court (HHJ Jarman KC, sitting as a High Court judge) made no order as to costs, on the brief basis that the claim had “become academic for political reasons after a change of government and not because of this claim”. PCSU appealed that costs order to the Court of Appeal.

1.2. The key issues

The appeal raised three interlinked issues:
  1. Success and costs in public law: Had PCSU, in substance, “succeeded” by achieving the repeal and non-use of the MSL Regulations, such that it should normally recover its costs?
  2. Causation: What causal link is required between judicial review proceedings and the outcome (here, political repeal) to justify an award of costs to a claimant when the claim settles or becomes academic?
  3. Political change as a reason for refusing costs: Can a change of government and ensuing policy shift be treated as an “extrinsic” reason that breaks the causal connection between litigation and outcome, even where the new policy “vindicates” the substance of the claim?
PCSU argued that its challenge had been vindicated and that denying it its costs on the basis of a change of government was inconsistent with the principle that the state’s legal responsibilities are continuous regardless of the party in office. The Secretary of State argued that PCSU had not demonstrated that the claim caused or accelerated the repeal; rather, the outcome followed from pre‑existing political commitments, so there was no basis for treating PCSU as the “successful party”.

1.3. The significance of the decision

This judgment refines the law on costs in judicial review where: - the public authority concedes or changes position; and - that change is driven by political factors, including a change of government, rather than by a recognition that the claim would (or probably would) succeed. The Court of Appeal confirms and sharpens a principle emerging from earlier authorities (Speciality Produce, ZN (Afghanistan), RL v Croydon, Parveen): where the outcome would have occurred anyway for reasons extrinsic to the litigation, the claimant has no prima facie entitlement to costs unless it is “tolerably clear” that they would likely have won on the merits. The novelty here lies in the explicit treatment of an electoral change of government and manifesto‑driven repeal as such an “extrinsic reason”.

2. Summary of the Judgment

2.1. Holding

The Court of Appeal (Bean LJ giving the leading judgment, with Peter Jackson LJ and Elisabeth Laing LJ agreeing) dismissed PCSU’s appeal. Key conclusions:
  • The first‑instance judge’s short reasons were sufficient: he had clearly based his decision on the view that the claim had become academic for political reasons, not because of the claim itself.
  • There was no error of principle or law in treating the change of government and pre‑existing Labour commitment to repeal the 2023 Act as an “extrinsic reason” for the outcome, breaking the causal link between the judicial review and the repeal/non‑use of the Regulations.
  • PCSU did not argue (and realistically could not argue) that it was “tolerably clear” it would have succeeded at trial on its Article 11 and ultra vires grounds. Article 11 challenges are recognised as inherently uncertain and “not usually easy victories”.
  • The Minister’s letter referring to the Act as “unduly restrictive” did not amount to a legal concession that the Regulations were unlawful or that the claim would have succeeded.
  • Accordingly, this was not a case in which PCSU could be treated as the “successful party” for the purposes of CPR 44.2, and the judge was entitled to make no order as to costs.

2.2. Disposition

- Appeal dismissed. - The “no order as to costs” made by HHJ Jarman KC stands. - The Court expressly recognised that the case was “quite close to the borderline”, but the high threshold for appellate interference with costs decisions (from Roache) was not met.

3. The Precedents and Legal Framework

The judgment integrates a line of authority on costs in public law, especially where cases settle or become academic.

3.1. Appellate restraint in costs appeals – Roache v News Group

The starting point (para 22) is Roache v News Group Newspapers Ltd [1998] EMLR 161. Sir Murray Stuart‑Smith stated that an appellate court may interfere with a costs order only where:
  • the judge erred in principle in their approach; or
  • left out of account a relevant factor or took into account an irrelevant one; or
  • the decision is “wholly wrong” so that the judge must have failed properly to balance material factors.
This stringent threshold, repeatedly approved (e.g. in Burgess v Lejonvarn and Parveen), shaped the Court of Appeal’s reluctance to overturn HHJ Jarman’s discretionary decision.

3.2. The core framework for costs where claims settle – R (M) v Croydon LBC

Bean LJ then relies heavily on Lord Neuberger MR’s judgment in R (M) v Croydon LBC [2012] EWCA Civ 595; [2012] 1 WLR 2607, which established the modern framework for costs in judicial review where relief is granted without a full trial. Key points from M v Croydon:
  1. Three general principles in ordinary civil litigation (para 24 of this judgment):
    • Costs decisions are for the trial judge, and appellate courts must be “very slow indeed” to interfere.
    • Default rule: “costs follow the event” – the successful party recovers costs (CPR 44.3(2)(a)), subject to discretion based on issues, conduct, etc.
    • The funding basis of a claim (e.g. no win/no fee, legal aid, pro bono) is generally irrelevant to costs liability.
  2. Consent orders and settlement:
    • Where the claimant obtains all the relief sought by consent, there is a strong presumption that they are the successful party and should normally get their costs (para 49).
    • Where they get only part of the relief, or the settlement doesn’t track the pleaded claims, the position is less clear; often no order as to costs will be made unless it is reasonably clear who would have won if the case had gone to trial (paras 50–51).
  3. Categories in public law (para 60–61 of this judgment):
    • Category (i): claimant wholly successful (contested hearing or settlement). Normally recovers all costs, absent special circumstances.
    • Category (ii): claimant partially successful. More complex; sometimes no order is appropriate.
    • Category (iii): compromise which does not directly reflect the claim. Default is often “no order” unless the court can see, without disproportionate effort, who would likely have won.
Bean LJ treats the typical post‑Bahta, post‑M v Croydon situation – where a public authority concedes and reconsiders a decision following pre‑action correspondence and issue of proceedings – as a Category (i) scenario: the claimant is usually the successful party and entitled to costs (para 44).

3.3. Partial success and “what counts as success” – Tesfay

In R (Tesfay) v Secretary of State for the Home Department [2016] EWCA Civ 415; [2016] 1 WLR 4853, the Court emphasised that in public law the notion of “success” is often more nuanced: - A claimant may “succeed” only in obtaining a lawful reconsideration (not necessarily a favourable substantive outcome). - Success must be assessed in relation to what was realistically achievable in public law (para 28 of this judgment). That nuance underpins the idea that obtaining a reconsideration, or a fresh decision, will often justify costs – but it still presupposes a causal link between the proceedings and the relief obtained.

3.4. Causation where parallel routes exist – Speciality Produce

In Speciality Produce Ltd v Secretary of State for the Environment [2014] EWCA Civ 225; [2014] CP Rep 29, the appellant pursued: - an internal statutory appeal; and - a judicial review alleging abuse of process. It won via the appeal route; the judicial review was then discontinued. Vos J (upheld by the Court of Appeal) refused to award costs of the judicial review: - The claimant had “backed two horses”, both properly; one (the appeal) came in first. - The key question was whether the claimant was likely to have succeeded on the abuse of process ground (the JR) (para 39). - Because it was not possible to say that without undue effort, the default was “no order as to costs”. Patten LJ crystallised the principle (para 30 of this judgment, quoting [29] in Speciality Produce): > “for that link [between claim and relief] to be established the court is, I think, usually required to be satisfied that the claimant is likely to have won … In any event, the claim must be causative of the relief obtained.”

3.5. “Would have happened anyway” – RL v Croydon

In R (RL) v Croydon LBC [2018] EWCA Civ 726; [2019] 1 WLR 224, the claim challenged delay in a statutory assessment leading to accommodation. The assessment was completed shortly after the claim; the claim was withdrawn; no order as to costs was made. Underhill LJ held: - The fact that the assessment was eventually completed did not itself represent “success”; that was going to happen anyway. - To justify costs, the court would have had to be satisfied that, as a result of the proceedings, the assessment was completed substantially sooner than it would otherwise have been (para 33 of this judgment, quoting [74] in RL). - On the facts, that could not be shown. Thus timing and causation are central: if the outcome would have occurred regardless of the claim, the claimant is not “successful” for costs purposes.

3.6. Extrinsic reasons and the Secretary of State’s “administrative failures” – ZN (Afghanistan)

In ZN (Afghanistan) v Secretary of State for the Home Department [2018] EWCA Civ 1059, the Secretary of State agreed (mid‑appeal) to consider asylum claims afresh. The asylum seekers sought costs, arguing that they had effectively obtained the relief sought. Singh LJ and Leggatt LJ emphasised: - Causal connection between the legal challenge and the relief is normally required (para 34 of this judgment, esp. [65], [67]–[69] in ZN). - Where the appeal becomes academic for an “entirely extrinsic reason” (e.g. change in country conditions), costs will not be awarded. - Even where the trigger is an “administrative failure” by the Secretary of State, if that failure is extrinsic to the litigation, it is not the sort of “conduct” with which CPR 44.2(4)(a) is concerned. Leggatt LJ added (para 35 of this judgment, [102]–[103]) that: - Access to justice considerations mean courts should try to identify whether the claimant achieved any material part of the relief sought. - The bar for “success” should not be set unduly high. - But again, this presupposes some causal link between the litigation and the benefit achieved.

3.7. Causation as potentially decisive – Parveen

In R (Parveen) v Redbridge LBC [2020] EWCA Civ 194; [2020] 4 WLR 53, Males LJ confirmed (para 36 of this judgment, quoting [31]): > “The fact that the claimant has obtained the relief which he or she was seeking in the proceedings does not necessarily mean that the existence of the proceedings has caused or contributed to that result. It may be that it would have happened anyway. The cases show that causation is a relevant and sometimes decisive factor in the exercise of the court's discretion concerning costs.” This encapsulates the principle that underpins the outcome in PCSU’s case.

3.8. The Bahta line and “pragmatic reasons”

PCSU invoked R (Bahta) v SSHD [2011] EWCA Civ 895; [2011] 5 Costs LR 857 (referred to in the judgment), which began a shift away from the Home Office’s historic practice of resisting costs on the basis that a concession was made for “purely pragmatic” reasons. The Court of Appeal here accepts that: - After Bahta and M v Croydon, the typical case in which the Secretary of State agrees to reconsider a decision following the issue of proceedings falls into Lord Neuberger’s Category (i) – claimant normally recovers costs (para 44). However, later authorities (Speciality Produce, RL, ZN, Parveen) illustrate that this does not create an automatic entitlement: the claimant must still show some causative link between the proceedings and the relief – or that they were likely to have won had the matter not become academic.

4. The Court’s Legal Reasoning in PCSU v SSHD

4.1. What the first‑instance judge actually decided

HHJ Jarman KC’s costs ruling was extremely short (para 21):
(1) The appropriate conclusion on the basis of the submissions is that the claim became academic for political reasons after a change of government and not because of this claim. (2) The other points made are noted but do not impact upon that conclusion. (3) In those circumstances the above cost order is just and proportionate.
The Court of Appeal accepted that this “telegraphic brevity” nonetheless clearly revealed his reasoning (para 42): - He concluded that the change of government and political decision to repeal and not use the Regulations were not caused by the judicial review. - Therefore PCSU could not rely on the usual “successful party” approach. The appellate question was whether that conclusion involved an error of principle or was otherwise outside the permissible ambit of judicial discretion.

4.2. PCSU’s three grounds and the Court’s response

PCSU advanced three grounds (para 37):
  1. The judge failed properly to address that PCSU had achieved substantial success.
  2. The judge made an unevidenced factual finding (that the outcome was for political reasons, not because of the claim) and/or applied the wrong test.
  3. The judge failed to engage with submissions and/or gave inadequate reasons.
The Court’s treatment, in essence, was: - Grounds (1) and (2) turned on causation and characterisation of the outcome. The Court held the judge had been entitled to treat the result as one driven by pre‑existing political commitments, not as litigation‑caused success. - Ground (3) failed because, although brief, the judge’s reasons were sufficient and intelligible, and appellate intervention on costs is tightly constrained by Roache.

4.3. Continuity of government vs causation for costs

PCSU advanced a powerful constitutional argument (para 39) that: - The state, and great offices of state (such as the Home Secretary), are continuous in law. - An incoming government cannot disassociate itself from, or be absolved of legal responsibility for, the acts of its predecessor. - Therefore, the fact that repeal is enacted by a government which had previously opposed the legislation should not prevent costs being awarded against the (continuing) office of Secretary of State. Bean LJ agreed with the constitutional premise (para 43): > “an incoming Government or incoming Secretary of State 'cannot be absolved of [legal] responsibility for the acts of the previous administration'.” However, he held this did not answer the causation question for costs. The Government was not claiming to be absolved of responsibility for the original MSL Regulations; rather, it argued: - that the repeal (and the non‑use commitment) flowed from earlier political commitments and would have occurred irrespective of the litigation; and - that this broke the causal link necessary to treat PCSU as the “successful party”. Thus continuity of legal responsibility for substantive wrongs does not equate to an entitlement to costs where a successor administration decides, for its own political reasons, to change course.

4.4. The role of Bahta and M v Croydon

The Court accepted PCSU’s broader point that Bahta and M v Croydon marked an important shift away from the old “no order for costs” default where the Home Office settled cases for “pragmatic reasons” (para 44): - In the “typical case” post‑Bahta, where the Secretary of State agrees to reconsider a decision because of the challenge, the claimant falls within Lord Neuberger’s Category (i) and will normally get costs. - However, that does not displace the need to show causation when the defendant’s change of position is said to arise for reasons unconnected with the litigation. The Court then stressed that later Court of Appeal decisions have clarified that: - Where a claim becomes academic “for reasons not attributable to the issue of proceedings”, there is “no prima facie entitlement to costs”, unless: - it is “tolerably clear” (without a mini‑trial) that the claimant would likely have succeeded (para 45); or - the proceedings can otherwise be shown to have materially affected the outcome or its timing (as in RL).

4.5. No “tolerably clear” likelihood of success on Article 11

Bean LJ acknowledged (para 45) that PCSU had not – realistically – suggested that it was tolerably clear that it would have won at trial: - Article 11 challenges are typically complex and fact‑sensitive. - Domestic and Strasbourg case law on restrictions to the right to strike (especially in essential services and national security contexts) tends not to yield “easy victories” for claimants. - There was no basis for the Court, on a summary costs application, to conclude that PCSU would likely have succeeded on its Article 11 / ultra vires grounds. This was an independent reason why PCSU could not rely on the “likely to have won” route identified in Speciality Produce and RL.

4.6. The Minister’s letter and the phrase “unduly restrictive”

PCSU placed weight on the Minister’s description of the 2023 Act as “unduly restrict[ing] the right to strike and undermines good industrial relations”, arguing this implicitly accepted the Article 11 incompatibility and vindicated its claim. Bean LJ rejected that reading (para 46): - The phrase “unduly restrictive” simply reflected the Labour Party’s long‑standing political view of minimum service level legislation, dating back to the passage of the 2023 Bill in Parliament. - It could not be read as a legal concession that: - the MSL Regulations were incompatible with Article 11; - the Regulations were ultra vires the 2023 Act; or - any interference with Article 11 went beyond the permissible “margin of appreciation” enjoyed by national authorities in regulating industrial action. Thus the letter did not constitute an admission that PCSU’s judicial review was bound to succeed or that the change of position was legally driven by the litigation.

4.7. Political commitment as an “extrinsic reason”

The decisive step (para 47) is the Court’s characterisation of Labour’s repeal pledge and subsequent conduct as an “extrinsic reason” for the outcome, applying the approach in ZN (Afghanistan) and Parveen: - The Labour Party’s commitment to repeal the 2023 Act and revoke MSL Regulations was clear and pre‑dated the claim. - There was “good reason to believe it would have come about in any event” even had PCSU not brought its judicial review. - Using Singh LJ’s language in ZN, the outcome was achieved “for an extrinsic reason”. - In Males LJ’s terms (Parveen), it is likely that the result “would have happened anyway”. The Court accepted that PCSU “got what it wanted” (repeal and non‑use), but stressed: > “it has not shown that it got what it wanted, or even got it more quickly, because of the issue of the claim.” (para 47) This is the critical conclusion on causation.

4.8. Borderline case, but within the judge’s discretion

Finally, Bean LJ acknowledged (para 48) that the case was “quite close to the borderline”. Nonetheless: - The judge’s decision fell within the proper scope of his discretion. - No error of law or principle was shown. - Given the high bar for interfering in costs orders (from Roache), the appeal had to be dismissed.

5. Analysis and Commentary

5.1. The core principle clarified: political change as “extrinsic” for costs

The judgment solidifies a crucial refinement in the law of costs in public law:
Where a claim for judicial review becomes academic because an incoming government, consistently with clear pre‑existing political commitments, changes or undertakes to change the law in the claimant’s favour, that political change will ordinarily be treated as an “extrinsic reason” for the outcome. Absent evidence that the litigation materially caused or accelerated that change, or that it is tolerably clear the claimant would have succeeded on the merits, the claimant has no prima facie entitlement to costs.
This aligns with, but extends, earlier “extrinsic reason” cases such as: - ZN (Afghanistan) – where appeals became academic due to administrative failures by the Secretary of State, extrinsic to the litigation. - Hypothetical scenarios posited there (para 68) – country conditions changing independently of the appeal. - RL v Croydon – where a statutory assessment would have been completed in any event. The novel element here is the application of that principle to deliberate political choices by a new government, even where those choices mirror the relief sought by the claimant and express agreement with the claimant’s normative critique of the legislation.

5.2. Burden (in practice) on claimants to show causation

Formally, the decision does not explicate a strict legal “burden of proof” in evidential terms. But in practice, its effect is clear: - Where the defendant says the outcome is the product of extrinsic reasons (here, political commitments and democratic mandate), the claimant will need to point to material indicating that: - the proceedings prompted the change; or - the change occurred earlier than it otherwise would have because of the claim (as in the timing‑based reasoning of RL v Croydon). PCSU argued that no authority placed an evidential burden on a claimant to prove causation and that Bahta prevents a defendant simply invoking “pragmatic reasons” without explanation (para 40). The Court did not deny that Bahta requires clarity from defendants, but it held, in substance: - The political origins and continuity of Labour’s repeal policy were public, clear, and pre‑existing. - There was no material showing that the litigation altered the Government’s course or timetable. - In those circumstances, the judge could properly infer that the claim played no causative role. For future litigants, the practical message is that where a policy shift or repeal aligns closely with a party’s manifesto and longstanding platform: - the litigation will rarely be seen as having caused the outcome; and - costs recovery will require specific evidence that the proceedings influenced the timing or form of the change.

5.3. Distinguishing continuity of responsibility from causation for costs

The judgment draws a subtle but important line between: - Substantive legal responsibility (continuity of the Crown and ministerial offices) – unaffected by a change of government; and - Causation for costs – a question about why the specific outcome (here, repeal and non‑use) occurred when it did and on what basis. PCSU’s constitutional submission – that an incoming administration cannot wash its hands of past acts – is correct in terms of liability and legal continuity. But for costs purposes, the issue is not who bears responsibility for the original measure; it is why the measure was revoked and why the litigation became academic. On that narrower question, the Court found: - The new Government’s conduct was driven by its own political programme, not by the litigation. - Therefore, the continuity principle does not compel an order for costs where the causative factor is an independent electoral mandate rather than judicial pressure.

5.4. Relationship with access to justice and Bahta/M v Croydon

There is a tension between: - The Bahta/M v Croydon impetus toward ensuring successful claimants in public law are not deprived of costs merely because the defendant concedes late or for “pragmatic” reasons; and - The insistence, in Speciality Produce, RL, ZN, Parveen, and now PCSU, on a meaningful causal link between proceedings and outcome. Bean LJ reconciles this by: - Recognising that in the “typical” judicial review settlement – where a decision is reconsidered following the pre‑action letter and issue of proceedings, and no extrinsic cause is apparent – the presumption of success and costs for the claimant remains strong (para 44). - Reserving “extrinsic reason” analysis for cases where the defendant can point to a clear independent driver of the outcome: e.g. changed country conditions, statutory appeal success, or, here, a change of government implementing a manifesto commitment. The judgment thus preserves the core access‑to‑justice thrust of Bahta while preventing claimants from recovering costs in circumstances where litigation has, in reality, not altered the course of events.

5.5. Strategic implications for trade unions and public interest litigants

For unions and NGOs challenging politically contentious legislation near election cycles, this case has important strategic implications:
  • Timing vs. costs risk:
    • If a hostile government enacts contested legislation shortly before an election and a challenger issues proceedings, but a new government comes in on a platform of repeal, the challenger may well fail to recover costs even if the legislation is reversed and never used.
    • This may tilt the calculus for litigants deciding whether to file proceedings in the last months of a parliament where a change of government is reasonably likely and manifesto positions are clear.
  • Evidence‑gathering on causation:
    • Claimants may need to seek disclosure or rely on public statements showing that litigation prompted reconsideration, accelerated reform, or shaped its content.
    • Absent such evidence, courts will be slow to infer that proceedings, rather than politics, made the difference.
  • No implied admission from political agreement:
    • Even strong political language by a new administration (e.g. describing legislation as “unduly restrictive”) will not, without more, be treated as an admission of legal unlawfulness sufficient to ground costs recovery.
    • Political critique is not equivalent to a concession that a measure is ultra vires or incompatible with Convention rights.

5.6. The unresolved Article 11 question

The judgment underlines that: - There has been no judicial determination that the MSL Regulations or the 2023 Act breach Article 11 or are ultra vires. - The Court expressly states that Article 11 cases are complex and not typically easy wins (para 45). - The Minister’s letter is not treated as a concession on Article 11 compatibility. Thus, while PCSU’s political campaign succeeded (the regime is to be repealed and not used), the legal status of similar minimum service level regimes under Article 11 remains open. That means: - Future governments (of any political stripe) seeking to introduce MSLs will have to navigate the Article 11 terrain afresh. - Claimants contemplating challenges to any successor legislation cannot treat PCSU’s case as a binding legal condemnation of MSLs; they will need to litigate the proportionality and margin‑of‑appreciation issues on their own facts.

6. Complex Concepts Explained

6.1. Judicial review and “academic” cases

Judicial review is the process by which the courts supervise the legality of decisions and actions of public bodies. The court does not substitute its own decision for that of the public authority; it asks whether the authority acted lawfully, fairly, rationally, and compatibly with human rights. A case becomes “academic” where there is no longer a live dispute requiring resolution – for example: - the impugned decision has been withdrawn; - the claimant has already received what they sought; or - circumstances have changed so that the remedy would have no practical effect. Courts may still hear academic cases in exceptional public interest situations, but usually they will decline to proceed. However, even when a claim is discontinued as academic, the question of who pays the costs incurred up to that point remains, often requiring careful analysis of success and causation.

6.2. Article 11 ECHR and the margin of appreciation

Article 11 ECHR protects: - the right to freedom of peaceful assembly; and - the right to freedom of association, including the right to form and join trade unions. It is not absolute. Interference is permitted if:
  1. It is “prescribed by law”;
  2. It pursues a legitimate aim (e.g. national security, public safety, protection of the rights and freedoms of others); and
  3. It is “necessary in a democratic society” – in essence, proportionate to that aim.
In trade union and strike contexts, the European Court of Human Rights recognises a “margin of appreciation” – a degree of discretion afforded to national authorities in balancing competing interests (e.g. continuity of essential public services vs the right to industrial action). The limits of that margin are often contentious and fact‑sensitive. PCSU’s challenged Regulations required border services to be “no less effective” on strike days than on non‑strike days. Whether that goes beyond the permissible margin and effectively extinguishes the right to strike is a complex proportionality question that the courts did not reach in this case.

6.3. Minimum Service Levels and “work notices”

Under the 2023 Act and the MSL Regulations: - The Government can set minimum service levels in specified sectors (including border services) during strikes. - Regulation 3 empowered the Home Secretary to issue a “work notice” to unions, specifying which workers must work to maintain those levels. - The union must take “reasonable steps” to ensure those named workers comply and do not strike. - Failure to comply removes the union’s statutory immunity from tort claims; non‑compliant workers lose protection against detriment or dismissal. Such regimes are controversial because: - they can significantly weaken the practical effectiveness of strikes; - they shift responsibility (and legal risk) onto unions; and - they raise questions about whether they amount to a disproportionate interference with Article 11 rights.

6.4. “Costs follow the event” and CPR r.44.2

In civil litigation, the default rule (CPR 44.2(2)(a)) is that: > “the general rule is that the unsuccessful party will be ordered to pay the costs of the successful party.” Judges can depart from this rule, taking into account factors such as: - each party’s conduct (including pre‑action behaviour and settlement attempts); - whether one party succeeded on particular issues but not others; - any admissible offers to settle; and - whether it was reasonable to pursue or defend the claim. In public law, the analysis is complicated by: - the non‑monetary nature of relief (e.g. quashing orders, declarations, reconsideration); - the fact that defendants are public bodies acting in the public interest; and - the frequency of settlements or withdrawals before a full hearing. The courts have therefore developed more nuanced notions of “success” and causation, as in M v Croydon and the subsequent line of authorities discussed above.

6.5. “Extrinsic reasons” vs causative concessions

An “extrinsic reason” for an outcome is one that: - lies outside the litigation process; and - would probably have occurred whether or not the claim was issued. Examples include: - altered country conditions in asylum cases; - a claimant succeeding on a parallel statutory appeal; - administrative errors by the defendant unconnected to the judicial review; or - as in PCSU’s case, a change of government implementing previously declared policies. By contrast, a causative concession is where the defendant’s change in position is prompted by the litigation itself – for example: - withdrawing an impugned decision in response to a pre‑action protocol letter; - granting the relief sought shortly after proceedings are issued with no other explanation. In the latter case, claimants will generally be treated as “successful” and entitled to costs (subject to reasonableness). In the former, they will not, unless they can show that the proceedings accelerated or shaped the outcome or that they were clearly likely to win on the merits.

7. Likely Impact on Future Cases

7.1. Costs in challenges to politically contentious legislation

This decision will be particularly relevant in cases where: - litigants challenge flagship legislation; - an election intervenes; and - a new government reverses course. Future claimants should expect that: - if the new government’s stance was clearly signalled in opposition or in its manifesto; - and if there is no evidence that litigation influenced the pace or content of repeal; then the courts are likely to treat repeal as driven by “extrinsic” political reasons and make no order as to costs.

7.2. Government litigation behaviour post‑change of administration

For successor governments and the GLD, the decision: - legitimises the stance that repudiating prior policies in line with a manifesto does not automatically carry costs consequences for ongoing judicial review claims brought under the previous administration; - will encourage clear documentary articulation of the reasons for policy shifts (e.g. manifestos, policy statements, ministerial letters), which can be relied upon to show an “extrinsic” basis; - but does not entitle the Government to avoid costs where there is evidence that litigation prompted or expedited change.

7.3. Access to justice and chilling effects

There is an inherent risk that: - litigants may be deterred from bringing challenges late in a political cycle if they anticipate that a likely change of government will yield their desired outcome while leaving them bearing their own costs; - this is particularly acute for unions and NGOs litigating on limited budgets. However, the decision also preserves important safeguards: - where causation is reasonably clear, or where it is tolerably clear that the claim would have succeeded, costs should still follow the event; - the court reaffirms the post‑Bahta principle that “pragmatic” concessions do not in themselves insulate public authorities from costs. In short, the case narrows, but does not close, the path to costs recovery in politically fluid contexts; the key will be evidence on causation and likelihood of success.

8. Conclusion

PCSU v Secretary of State for the Home Department [2025] EWCA Civ 1644 does not resolve the legality of minimum service levels in border security or their compatibility with Article 11. Instead, it makes a significant contribution to the law of costs in judicial review. The central takeaways are:
  • Causation remains central to costs in public law even where the claimant appears to have achieved the substantive outcome sought.
  • A change of government implementing a clear pre‑existing policy commitment to repeal or alter the impugned measure will generally be treated as an “extrinsic reason” for the outcome, breaking the chain of causation for costs.
  • Claimants wishing to recover costs in such circumstances must show either:
    • that the litigation materially caused or accelerated the change; or
    • that it is “tolerably clear” they would have succeeded on the merits.
  • Political agreement with the claimant’s normative stance (e.g. calling a law “unduly restrictive”) is not, without more, a legal concession of unlawfulness.
  • Appellate courts will remain “very slow indeed” to interfere with first‑instance costs decisions unless clear errors of principle or law are shown.
In the broader legal context, the case: - consolidates post‑Bahta doctrine on costs in compromised judicial review claims; - integrates the “extrinsic reason” and “would have happened anyway” lines of authority into the realm of political change and legislative repeal; and - sets a careful balance between encouraging access to justice and avoiding windfall costs awards where litigation has not altered the course of events. For trade unions, public interest organisations, and government litigators alike, the decision is a key authority on the interplay between political change, judicial review, and the allocation of costs.

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