Ministerial Primacy and De Novo Wiley Balancing in Inquests: Commentary on Secretary of State for Northern Ireland for Judicial Review [2025] UKSC 47

1. Introduction

This decision of the United Kingdom Supreme Court in Secretary of State for Northern Ireland for Judicial Review [2025] UKSC 47 addresses a crucial and previously unsettled question: what is the correct standard and method of judicial review when a coroner decides to disclose a “gist” of material covered by a ministerial Public Interest Immunity (“PII”) certificate on national security grounds?

The case arises out of the long-delayed inquest into the 1994 killing of Liam Paul Thompson at Springfield Park, Belfast, adjacent to a “peace line” separating nationalist and unionist communities. The key factual controversy is whether state agents (police, army or informers/CHIS) colluded with loyalist paramilitaries in the murder, or failed to prevent it despite prior intelligence and knowledge of security vulnerabilities.

The Police Service of Northern Ireland (“PSNI”) held sensitive documents relevant to these issues. The Minister of State for Northern Ireland, acting for the Secretary of State under the Carltona principle, certified that disclosure would create a real risk of serious harm to national security, invoking PII and the “neither confirm nor deny” (“NCND”) policy that protects covert human intelligence sources and methods. The coroner upheld PII over the documents themselves, but nonetheless sought to disclose two short summaries (gists) of information contained in one folder (folder 7).

The Secretary of State, supported by several other central government departments, challenged the coroner’s decisions. The High Court and a majority of the Court of Appeal in Northern Ireland treated the challenges as ordinary supervisory judicial review, upholding the coroner’s decisions unless unlawful, irrational or procedurally unfair. The Supreme Court unanimously takes a very different view: PII is a matter of substantive law, not discretion; appellate and reviewing courts must themselves perform the balancing exercise under Wiley; and, when the asserted public interest is national security, the Secretary of State’s assessment of risk must be accepted unless irrational or unsupported by evidence.

The judgment sets important new markers in several directions:

It clarifies that the Wiley PII balance is not a discretion but a question of law, so that appellate and reviewing courts must decide for themselves where the public interest lies.
It re‑frames the controversial “fifth Litvinenko principle” on deference to ministerial assessments of national security risk.
It identifies the Secretary of State as the primary constitutional actor and “clearing house” for national security assessments in PII disputes, even where police are the “information owners”.
It emphasises procedural duties on coroners to engage the Secretary of State before departing from ministerial views on risk and before ordering any gist disclosure.
It insists that coroners must factor in statutory time limits and the viability of an inquest when weighing the public interest in disclosure.

Ultimately, the Supreme Court allows the Secretary of State’s appeal and holds that neither gist should be disclosed. It points instead to a public inquiry or to the Independent Commission for Reconciliation and Information Recovery (ICRIR) as the appropriate vehicles to satisfy any residual obligations under Article 2 of the European Convention on Human Rights (“ECHR”).

2. Summary of the Judgment

2.1 Core holdings

Nature of PII decisions: Decisions whether material is excluded on PII grounds involve the application of substantive law, not the exercise of discretion. A coroner (or court) must correctly apply the Wiley balancing test, and appellate/reviewing courts must decide for themselves whether the balance was correctly struck.
Standard of review: Judicial review is not confined to traditional “Wednesbury” supervision when examining a coroner’s PII determination. The reviewing court must re‑perform the Wiley balance, while accepting the Secretary of State’s assessment of the existence and degree of national security risk unless irrational or unsupported by evidence.
Ministerial primacy on national security: Among public authorities with an interest in secrecy (here, PSNI and the Secretary of State), it is the Secretary of State who is constitutionally best placed, and politically accountable, to make the final assessment of national security risk. Other authorities (like the Chief Constable) should first consult and attempt to reach consensus; if differences persist, courts will generally look to the Secretary of State’s assessment.
Re‑statement of the “Litvinenko principle”: The Supreme Court disapproves the formulation that a minister’s view should be accepted unless there are “cogent or solid reasons to reject it”. The correct question is whether the minister’s assessment is irrational or unsupported by evidence. However, if a court departs from that assessment, it must give clear reasons.
Errors by the coroner:
- Applying only “proper regard” to the minister’s assessment, rather than accepting it subject to rationality/evidence review.
- Assuming the gists “mitigated or prevented” any real risk of serious harm and therefore omitting the Wiley balance.
- When alternatively purporting to balance interests, proceeding on the basis of only “limited harm to national security” instead of the minister’s assessed “real risk of serious harm”.
- Failing to obtain the Secretary of State’s views on gist disclosure, instead treating the PSNI/Chief Constable as the relevant decision-maker and PII applicant.
- Failing, when deciding to disclose gist 2 on 11 April 2024, to take into account that it was then impossible to complete the inquest before the statutory deadline of 1 May 2024.
Errors by the High Court and Court of Appeal:
- Treating the coroner’s decisions as exercises of a wide discretion subject only to ordinary public law review.
- Failing to recognise the coroner’s misapplication of the standard for departing from the ministerial risk assessment.
- Failing to insist that the Wiley balance be carried out on the basis of the minister’s assessment of risk.
- Overlooking the coroner’s omission to obtain and consider the Secretary of State’s views, a serious procedural defect.
- Failing to recognise that the 1 May 2024 statutory deadline was a material factor in the public interest balance.
Outcome on the facts: Performing the Wiley balance itself, the Supreme Court holds that:
- The public interest in open investigation via these particular gists is negligible—indeed, they were so high level and indeterminate that they would not support meaningful findings or prompt further admissible investigation.
- The national security interest, as assessed by the Minister and not irrational, remains weighty.
- The statutory bar on completing the inquest further diminishes any justification for disclosure.
- Accordingly, neither gist 1 nor gist 2 should be disclosed.
Article 2 ECHR: Any remaining obligation to investigate the death under Article 2 can be fulfilled through mechanisms that can handle sensitive material via closed procedures—specifically, a public inquiry under the Inquiries Act 2005 or an ICRIR review.

3. Factual and Procedural Context

3.1 The killing of Liam Thompson and the peace line

In April 1994, Liam Paul Thompson, aged 25, was fatally shot in Springfield Park, a nationalist area adjoining a peace line barrier separating it from the loyalist Springmartin Road. Gunmen, claimed by the Ulster Freedom Fighters (UFF), entered through a hole in the fence, attacked a taxi in which Thompson was travelling, and escaped back through the breach. No one has been convicted.

The community alleges:

Repeated prior attacks by loyalist paramilitaries via breaches in the peace line.
Warnings to the RUC, the Northern Ireland Office (NIO) and political representatives that the fence had been compromised on the day of the attack.
Evidence that loyalist paramilitaries were monitoring “Grab‑a‑Cab” taxis, including the discovery of a map of the taxi depot in a Royal Marine’s locker and references in the Brian Nelson papers.

Against this background, the inquest’s “scope” expressly included questions about:

Whether security force informants (CHIS) supplied information to the killers or to the security forces.
Whether state agencies failed to act on prior knowledge of the threat.
Whether the death was reasonably preventable.

3.2 The inquest and the Troubles Act deadline

The inquest, opened in 1995, suffered “lengthy, egregious and profoundly disturbing” delays. Substantive hearings finally commenced in 2023. The Northern Ireland Troubles (Legacy and Reconciliation) Act 2023 then imposed a deadline: under amended section 16A of the Coroners Act (NI) 1959, an inquest into a Troubles‑related death could not be “progressed” on or after 1 May 2024 unless, on that date, the only outstanding element was the coroner’s final determination or verdict.

Because of PII disputes and ensuing judicial review proceedings, the third and final module of the inquest could not be completed before that deadline. The coroner later held that, due both to the statutory time bar and to the exclusion on PII grounds of material she regarded as “of central importance”, the inquest had become non‑viable and could not properly answer the statutory questions, especially “how” the deceased came by his death in the broader Middleton/Maguire sense.

3.3 The PII certificates and folder 7

PSNI disclosed seven folders of potentially relevant material to the coroner. The Minister of State for Northern Ireland issued PII certificates in respect of folders 1–6 (5 February 2024) and folder 7 (19 February 2024), supported by a sensitive schedule. The Minister accepted that the material was relevant but certified that disclosure would create a real risk of serious harm to national security, mainly because:

Terrorist threats, though reduced, persisted in Northern Ireland.
Disclosure could expose individuals providing information in confidence or reveal tactics, techniques and procedures used to counter terrorism.
Exposure would endanger informants and impair the willingness of existing and potential CHIS to cooperate, in Northern Ireland and elsewhere.

The coroner upheld PII over folders 1–7 but proposed to disclose a high‑level gist of certain information from folder 7. A first draft (gist 1) and then a revised version (gist 2) became the focus of dispute:

The Chief Constable initially supported full PII and asserted that gist 1 would breach NCND and harm national security, then shifted to accept gist 2 as harmless.
The Secretary of State consistently maintained that any gist implying whether CHIS involvement or secret methods were or were not present would breach the NCND policy and carry national security risks.

Crucially, the coroner:

Did not show gist 1 to the Minister/Secretary of State before deciding to disclose it.
Treated the PSNI as the PII “applicant”, rather than the Minister as the constitutional decision-maker on the public interest.

3.4 The litigation trajectory

High Court (Humphreys J): Dismissed judicial review challenges to disclosure of gist 1 and gist 2, applying ordinary public law standards (illegality, irrationality, procedural unfairness) and affording the coroner a “generous width of discretion”.
Court of Appeal (Keegan LCJ, Horner LJ; McCloskey LJ dissenting):
- Majority upheld the High Court, again treating the coroner’s decisions as discretionary and subject to classic supervisory review.
- McCloskey LJ, dissenting, concluded that the coroner’s decisions were unlawful, that she had failed correctly to apply the test for departing from ministerial assessments of national security risk, and that she was not empowered to disclose gist 2 once the inquest could no longer be completed.
Supreme Court: Granted permission to appeal, appointed advocates to the court and special advocates, and ultimately allowed the Secretary of State’s appeal.

4. Precedents and Doctrinal Lineage

4.1 Wiley and the PII balancing exercise

The governing framework for PII claims remains that set out by the House of Lords in R v Chief Constable of West Midlands Police, Ex p Wiley [1995] 1 AC 274. Key points are:

PII involves balancing two aspects of the public interest:
- The interest in the administration of justice (or, in inquests, the proper investigation of a death), which favours disclosure of all relevant evidence.
- The interest in protecting other public values (e.g. national security, confidentiality, law enforcement), which may favour non‑disclosure.
If the public interest in non‑disclosure outweighs that in disclosure, the material must be treated as inadmissible. This is a matter of duty, not choice, for both Minister and court.
The final decision is for the court, but the court will ordinarily act on “the evidence of those best able to assess the importance of the public interest involved in making disclosure”.
Partial disclosure techniques, such as redaction or gisting, may sometimes reconcile the competing interests.

The Supreme Court in the present case embraces these principles but clarifies: (i) that the exercise is one of applying substantive law rather than exercising a discretion; and (ii) that the appellate/reviewing court must itself undertake the balancing, not simply review the reasonableness of the first instance decision.

4.2 Conway v Rimmer, Lewes Justices and ministerial assessments

Conway v Rimmer [1968] AC 910 and R v Lewes Justices, ex p Home Secretary [1973] AC 388 laid the foundation for judicial control over PII:

The courts, not ministers, have the final say on whether PII applies.
Nonetheless, ministerial assessments of where the public interest lies, especially on matters like national security, are “always valuable and may sometimes be indispensable” (Lord Reid in Lewes Justices).
The House of Lords in those cases itself inspected the documents and decided the public interest balance, confirming that appeals in PII cases are not confined to narrow reasonableness review.

The Supreme Court here relies on these authorities to reinforce its conclusion that appellate courts must perform their own Wiley balancing and are not bound by a first instance “discretion”.

4.3 Mohamed, Litvinenko and the “fifth principle”

In R (Mohamed) v Secretary of State for Foreign and Commonwealth Affairs (No 2) [2011] QB 218, the Court of Appeal addressed whether parts of a judgment should be redacted for national security reasons. Two points are important:

Lord Neuberger MR emphasised that, while a minister’s assessment of national security risk is entitled to great weight, the court must still decide where the public interest lies and may differ from the minister if his view is irrational or unsupported by evidence.
He stated expressly that the appeal court must decide whether the lower court’s PII decision was “right or wrong”, not merely whether the reasoning was flawed.

Sir Anthony May P, while using slightly different language (“no proper basis”), was to similar effect: the court should not substitute its own risk assessment unless the minister’s view is irrational or lacks an evidential foundation.

These ideas fed into the “Litvinenko principles” formulated by Goldring LJ in Secretary of State for Foreign and Commonwealth Affairs v Assistant Deputy Coroner for Inner North London [2013] EWHC 3724 (Admin), concerning PII in the Alexander Litvinenko inquest. The fifth Litvinenko principle stated that the Secretary of State’s assessment of damage to national security should be accepted unless there are “cogent or solid reasons to reject it”.

The Supreme Court now re‑casts this:

The “cogent reasons” formula is capable of misleading. The legal test is the familiar public law standard: is the minister’s assessment irrational or unsupported by evidence?
However, the discipline of requiring a court to give clear reasons if it declines to accept a minister’s assessment is endorsed and retained.

4.4 Deference, proportionality and national security: Begum, Shvidler, U3

The judgment situates its approach within a broader line of authority on deference to executive assessments in national security and foreign affairs:

R (Begum) v Special Immigration Appeals Commission [2021] AC 765: emphasising the institutional competence and democratic accountability of the Secretary of State in national security risk assessment.
U3 v Secretary of State for the Home Department [2025] UKSC 19 and Shvidler v Secretary of State for Foreign, Commonwealth and Development Affairs [2025] UKSC 30: discussing how courts should treat executive assessments when applying proportionality, and highlighting when appellate courts should form their own view (especially on major public interest questions affecting the rule of law and public confidence).

Drawing on these cases, the Court holds that:

The Secretary of State is “best placed” to act as the “clearing house” for national security assessments across different agencies.
Courts must accord “considerable respect and weight” to such assessments, but retain a supervisory role over their rationality and evidential basis.

4.5 Inquests and the Article 2 context: Middleton, Maguire, Dallaglio, Jamieson, Officer C

Several authorities frame the coroner’s investigative duties:

R (Middleton) v West Somerset Coroner [2004] 2 AC 182 and R (Maguire) v Blackpool and Fylde Senior Coroner [2025] AC 63: require Article 2‑compliant inquests to explore not just “by what means” but also “in what broad circumstances” the deceased died.
R v Inner West London Coroner, ex p Dallaglio [1994] 4 All ER 139 and R v Coroner for North Humberside and Scunthorpe, ex p Jamieson [1995] QB 1: emphasise the coroner’s duty to ensure that the relevant facts are “fully, fairly and fearlessly investigated”.
Re Officer C [2013] NILR 221: had been taken to suggest a wide discretionary margin for coroners in regulating their inquests, which the lower courts in this case extended into the PII sphere.

The Supreme Court distinguishes these cases. While coroners have latitude in shaping the scope and procedure of an inquest, PII determinations are a matter of substantive evidential law governed by Wiley, not a free‑standing discretion. The “wide discretion” language cannot be imported wholesale into PII decision‑making.

5. The Supreme Court’s Legal Reasoning

5.1 PII as substantive law, not discretion

The Court’s starting point is conceptual. PII is a rule of evidence dictating that certain relevant, otherwise admissible material must be excluded if, on balance, the public interest so requires. When a court or coroner decides whether PII applies, it is:

Identifying the relevant legal test (the Wiley balance), and
Applying that test to the facts in order to determine the rights and obligations of the parties, or the admissibility of evidence in an inquest.

It is not “exercising a discretion” in the sense of choosing between a range of acceptable outcomes. As a result:

An appellate court does not ask merely whether the first instance decision was within the range of reasonable conclusions. It must decide whether that decision was legally right or wrong.
Indeed, leading authorities like Conway, Lewes Justices, Wiley and Mohamed show appellate courts directly reassessing the public interest and inspecting documents for themselves.

This aligns with the Court’s broader approach in proportionality cases (such as Shvidler): issues which bear directly on the rule of law and public confidence, and which involve balancing powerful public interests, are for appellate courts to determine substantively.

5.2 The court’s role in assessing national security risk

The Supreme Court carefully distinguishes between:

The assessment of the existence and extent of risk to a particular aspect of the public interest (here, national security); and
The balancing exercise between that risk and the interest in the administration of justice/open investigation.

On the first, the court generally relies on ministers and relevant agencies:

Ministers, especially the Secretary of State, have institutional competence, democratic accountability and access to intelligence across agencies.
Courts must accept ministerial assessments on national security risk unless they are irrational or unsupported by evidence.

On the second, the court alone is responsible:

It must decide where the single public interest lies, synthesising its components.
It may give considerable weight to ministerial assessments of risk but is not bound by ministerial views on the ultimate balance between security and open justice.

The Court emphasises that this dual structure is not unusual: courts regularly apply legal tests involving value judgments (like proportionality) while according deference on certain factual or evaluative premises supplied by the executive.

5.3 Ministerial primacy and inter‑agency consultation

A central theme is how multiple public authorities should handle PII where national security is at stake:

Different bodies (e.g. PSNI, Security Service, other departments) may have overlapping equities in the same material and may initially take different views on risk.
The proper first step is not to litigate those differences in court, but to consult:

Authorities should attempt to reach a consensus through inter‑agency discussion.
If consensus is impossible, the authority with primary responsibility for national security—ordinarily the Secretary of State—should make the final assessment and present it to the court.

The Chief Constable’s approach in this case is criticised on two counts:

He changed position dramatically—first supporting the Minister’s PII claim and describing folder 7 as not amenable to gisting, then proposing gist 2 and asserting it carried no risk—without consulting the Secretary of State.
He did not alert the coroner to the possibility (indeed, reality) that the Secretary of State might disagree with his assessment, thereby denying the coroner the opportunity to seek ministerial views.

The Court also criticises the coroner for:

Misidentifying the “applicant” for PII as the PSNI rather than the Secretary of State, whose ministerial certificate grounded the claim.
Proceeding to order gist disclosure without obtaining the Secretary of State’s views on the specific proposals.

Constitutionally, the Court confirms that:

The Secretary of State is the key actor whose assessment of national security risk will ordinarily guide the court.
Other authorities should not treat national security as a matter to be contested with the Secretary of State before a court; rather, they jointly inform the minister’s assessment.

5.4 Re‑framing the Litvinenko principle and rejecting “cogent reasons”

The Court dissects the fifth Litvinenko principle. The prior formulation suggested that a minister’s assessment of national security risk should be accepted unless there are “cogent or solid reasons to reject it”. The Supreme Court replaces this with a more orthodox articulation:

The correct standard is whether the minister’s assessment is irrational or unsupported by evidence (classic public law review).
However, if a court rejects a minister’s assessment, it must explain its reasons clearly. This is a matter of judicial discipline, not an elevated threshold of “cogency” beyond ordinary rationality review.

In the present case:

The coroner accepted that there was some risk but purported to re‑scale it, effectively downgrading the Minister’s “real risk of serious harm” to a “limited” or negligible risk without finding the minister’s assessment irrational or unsupported by evidence.
This was impermissible. She was required to proceed on the basis of the Minister’s assessment when performing the Wiley balancing exercise.

5.5 Procedural duties of coroners in PII/gisting decisions

The Court stresses that coroners must exercise “great care” when dealing with PII and national security:

They are bound to protect national security as part of the general duty to protect the public interest, even where none of the “properly interested persons” presses the point.
They must ensure they are “fully and accurately” informed about the national security dimension before making decisions on disclosure or gisting.

Applied here:

The coroner should have sought the Secretary of State’s views on both gist 1 and gist 2 before making any decision.
It was not enough to say the Secretary of State could have applied to be a properly interested person or could have volunteered submissions; the coroner had a proactive obligation to obtain ministerial input given the obvious gravity of the asserted risk.
By failing to do so, she made decisions without considering a material factor—namely, the Secretary of State’s reasoned perspective on the specific proposed gists.

This amounts to procedural unfairness and a failure to have regard to relevant considerations.

5.6 The Troubles Act deadline as a mandatory consideration

On 11 April 2024, when the coroner decided to disclose gist 2, it was already clear that:

The 1 May 2024 deadline meant the inquest could not be completed.
As a result, no “final determination, verdict or findings” could ever be delivered.

This was crucial to the public interest balance:

The value of disclosure during an inquest normally lies in its contribution to a concluded set of findings, and its potential to prompt further inquiries.
Here, with the inquest unable to conclude and no further coronial investigation possible, the utility of gist disclosure in furthering the inquest’s statutory aims was radically diminished.

The Supreme Court holds that:

The coroner failed to take this into account when performing (or purporting to perform) the Wiley balancing exercise for gist 2; this was an error of law.
The suggestion that partial disclosure could nonetheless achieve some of the “goals” of an inquest—for example, reducing rumour and suspicion—was rejected. Without findings, a bare gist would not dispel suspicion; it would merely “leave the information ... hanging in the air” and invite speculation, the “antithesis” of a coronial investigation’s purpose.
While the Court leaves open the possibility that in exceptional circumstances a conclusive gist about, say, the identity of the deceased might legitimately be disclosed even if no inquest can conclude, that issue did not arise here and was not decided.

On the narrower, more immediate point, the failure to consider the deadline as a factor in the balancing exercise was itself sufficient to vitiate the coroner’s decision on gist 2.

5.7 The limited utility of the gists

Although not essential to its formal reasoning, the Court expresses “considerable doubt” about the practical significance of the gists:

Both gist 1 and gist 2 were “very short” and “very high level”, describing matters “at a very high level of abstraction” and in an “indeterminate” manner.
They would not realistically have enabled the coroner to make concrete findings on any material issue concerning how the deceased died.
They were unlikely to generate productive new lines of inquiry, since any such inquiries would engage the same PII problems that led to the exclusion of folders 1–7 in the first place.

Therefore, even apart from the statutory deadline, the Court considered that the marginal benefit to the inquest from gist disclosure was negligible when set against the assessed national security risks. That evaluation heavily informs its own Wiley balance.

5.8 The Court’s own Wiley balance

Applying the framework it has articulated, the Supreme Court:

Accepts the Minister’s assessment that disclosure (even in gist form) would create a real risk of serious harm to national security, including:
- Undermining the NCND policy that protects CHIS.
- Deterring current and potential informants, in Northern Ireland and beyond.
- Risking exposure of covert methodologies.
Finds that the gists would confer very little benefit to the inquest’s fact-finding function, especially given:
- Their abstract nature.
- The impossibility of completing the inquest by 1 May 2024.
- The coroner’s own conclusion that, without the full PII‑protected material, she could not conduct a proper and sufficient investigation.

Balancing these factors, the Court concludes that the overall public interest clearly favours non‑disclosure. Accordingly, PII must be upheld and neither gist may lawfully be disclosed.

6. Impact and Implications

6.1 Consequences for coronial practice and legacy inquests

The judgment substantially recalibrates the legal framework within which coroners handle PII and gisting:

No “wide discretion” in PII determinations: Coronial decisions on PII are not mere exercises of procedural discretion. They are determinations of substantive evidential law and are subject to close appellate scrutiny.
Mandatory ministerial engagement: When PII is asserted by a Minister, coroners must treat the Secretary of State as the primary national security decision‑maker. Before gisting or partially disclosing sensitive material, they must obtain and consider the minister’s specific views on any proposed gist.
Care with gisting: Coroners should scrutinise carefully whether a gist will genuinely advance the fact-finding process, or merely generate controversy and speculation. If a gist adds little to the capacity to reach meaningful findings, and carries any significant security risk, the public interest will usually favour non‑disclosure.
Time‑limit as a balancing factor: Inquests affected by statutory cut‑offs (like the Troubles Act 2023) must factor those constraints into any decision whether to disclose sensitive material. The nearer the inquest is to being unable to conclude, the weaker the rationale for risking national security to benefit its fact-finding.

In practice, for Troubles‑era inquests now constrained by the 2023 Act, it will be difficult to justify disclosure of sensitive national security material—especially where:

The inquest cannot complete before the statutory deadline; and
Material is subject to ministerial PII on CHIS or methodology grounds.

This point is underscored by the Court’s suggestion that Article 2‑compliant investigation may instead have to proceed via inquiries or ICRIR reviews, which can use closed procedures.

6.2 Broader PII practice: ministerial certificates and evidence

The judgment also contains guidance of general application beyond inquests:

Level of detail in PII evidence: The Court criticises an affidavit from a Security Service officer that contained only general, theoretical assertions about harm, unconnected to the specific documents. It warns against “purely formulaic” evidence and emphasises the “discipline” of articulating concretely why particular material engages the public interest in non-disclosure.
Co‑ordination among agencies: Police forces and other “information owners” should consult with ministers and sister agencies and avoid unilateral shifts in position, particularly in sensitive areas such as CHIS management and NCND.
NCND policy’s systemic dimension: The Court highlights that NCND is not merely about individual CHIS safety in Northern Ireland; it also concerns global perceptions amongst informants and prospective informants that the UK can be trusted to protect them, including in foreign theatres. This broad framing will likely influence PII claims about intelligence across different domains.

Practitioners can expect to see:

More demand from courts for PII certificates and supporting evidence that explain, with some specificity, why given material is sensitive.
Continued, and possibly enhanced, judicial respect for ministerial assessments where proper, case‑specific reasoning is provided.

6.3 Article 2 ECHR and alternative mechanisms

The decision starkly illustrates the tension between:

Article 2 ECHR’s procedural duty to investigate deaths involving potential state responsibility, and
The constraints of national security secrecy and the Troubles Act’s cut‑off for legacy inquests.

The Court endorses the coroner’s view that, given the scope and sensitivity of the PII‑protected material and the absence of a closed material procedure for inquests, a public inquiry may be required to meet any ongoing investigative duty. It also points explicitly to the ICRIR as a body capable of:

Receiving and assessing closed material.
Conducting Article 2‑compliant investigations with appropriate security safeguards.

The implication is that, for many Troubles‑related deaths where key evidence is secret or CHIS‑sensitive, inquests will no longer be the primary vehicle for investigation. This is a significant shift in the landscape of legacy justice in Northern Ireland.

6.4 Transparency, policing and public confidence

The Chief Constable’s submissions referenced the Patten Report’s emphasis on police transparency and the presumption of openness unless the public interest demands otherwise. The Supreme Court expresses “considerable sympathy” with that aim, but insists that:

National security is not to be underestimated; it is “a public interest of first importance” (echoing Brind).
The proper route to reconcile transparency and secrecy is via structured PII analysis led by the Secretary of State, not unilateral police disclosures that may cut across national security assessments.

This may disappoint those advocating for more aggressive disclosure around alleged collusion during the Troubles. Yet the judgment does not deny the importance of transparency; instead, it channels it toward mechanisms capable of handling secret material (inquiries, ICRIR) rather than open inquests where no closed procedure exists.

7. Complex Concepts Simplified

7.1 Public Interest Immunity (PII)

PII is a legal rule allowing relevant evidence to be withheld from court proceedings when its disclosure would harm the public interest—for example, by endangering national security, revealing informants, or undermining law enforcement techniques. The court balances:

The interest in having all relevant evidence available for justice to be done; against
The interest in protecting some other important public value.

If the harm outweighs the benefits of disclosure, the material is treated as inadmissible even though it is relevant.

7.2 The Wiley balancing test

Under Wiley, the court asks:

Is there a genuine, substantial public interest in non-disclosure (e.g. national security, CHIS protection)?
Is there a genuine public interest in disclosure (e.g. fair trial, effective investigation, public scrutiny)?
Which is weightier on the facts of the particular case?

If non-disclosure prevails, the material cannot be used in court—even if that harms one party’s case.

7.3 “Neither confirm nor deny” (NCND)

NCND is a policy whereby public authorities refuse to confirm or deny whether a particular person is an informer or agent. The reasons include:

Confirming that X is an agent could put X in immediate danger.
Denying that Y is an agent, while refusing to answer about Z, can indirectly identify Z as an agent.
If agents fear the state may expose them, they will be less willing to provide crucial intelligence.

In this case, NCND is engaged not because any named individual’s status is at stake, but because confirming or denying CHIS involvement or methods in these events could chill existing and future sources, in Northern Ireland and beyond.

7.4 CHIS

A Covert Human Intelligence Source (CHIS) is an undercover source—an informant or agent who secretly provides intelligence to the authorities, often embedded within criminal or terrorist organisations. Their safety depends heavily on secrecy. They are central to modern counter‑terrorism and organised crime strategies.

7.5 Wednesbury irrationality

A decision is “Wednesbury irrational” (from Associated Provincial Picture Houses Ltd v Wednesbury Corporation [1948] 1 KB 223) if it is so unreasonable that no reasonable decision‑maker could have made it. In this judgment, that standard is used to define the boundary of permissible disagreement with ministerial assessments of national security risk.

7.6 “Anxious scrutiny”

“Anxious scrutiny” is a phrase sometimes used where rights are at stake, indicating a more intensive review than ordinary Wednesbury irrationality but short of full merits review. The Supreme Court clarifies that, in PII cases, the appropriate framework is not anxious scrutiny but the Wiley balancing exercise, which appellate courts must themselves undertake, coupled with ordinary rationality review of ministerial risk assessments.

7.7 The Carltona principle

Under the Carltona doctrine (Carltona Ltd v Commissioners of Works [1943] 2 All ER 560), acts of a junior minister or official are treated as acts of the Secretary of State. Here, the Minister of State for Northern Ireland signed the PII certificates, but he did so on behalf of the Secretary of State, who is legally treated as the decision-maker.

7.8 Closed material procedure vs inquests

A “closed material procedure” allows a court, in certain statutory contexts, to see secret material that cannot be shown to one party, relying on special advocates instead. The Justice and Security Act 2013 provides for this in some civil proceedings. Inquests, however, do not have such a procedure. Therefore:

Either the material is admitted and fully disclosed; or
It is excluded on PII grounds.

This structural feature strongly influences the Court’s view that inquests may not be the right forum for highly sensitive national security material.

8. Conclusion

Secretary of State for Northern Ireland for Judicial Review [2025] UKSC 47 is a significant realignment of the law on PII in the context of inquests, with ramifications across public law and national security litigation.

The Court holds that PII decisions are applications of substantive law, not exercises of broad discretion. Judicial review and appellate courts must themselves decide whether the Wiley balance has been correctly struck, though they must accept ministerial assessments of national security risk unless irrational or unsupported. The “fifth Litvinenko principle” is refined: courts must give reasons if they depart from ministerial assessments, but the underlying test is the familiar rationality/evidence standard, not a heightened “cogent reasons” threshold.

Constitutionally, the decision emphasises the Secretary of State’s primacy in national security assessments and the need for inter‑agency consultation before PII disputes reach court. Coroners are reminded that they bear a duty to protect national security, must seek ministerial views on proposed gists, and must carefully weigh statutory constraints—such as the Troubles Act deadline—when deciding whether any disclosure is justified.

On the facts, the Court concludes that the marginal benefit of the proposed gists to an inquest that could no longer conclude was negligible, while the assessed risk to national security, including the integrity of the NCND policy and the CHIS system, remained substantial. The appeal is therefore allowed and neither gist may be disclosed.

In the wider legal landscape, the judgment underscores that difficult questions about historic killings involving alleged collusion may need to be addressed through inquiries or specialised bodies like the ICRIR, capable of handling sensitive intelligence in closed procedures. It thus marks a decisive doctrinal development at the intersection of open justice, national security, and the legacy of the Northern Ireland conflict.