ALERTER
The admissibility of disclosure, evidence and reports arising from public inquiries in subsequent proceedings after Evans v Barclays

By Tim Green KC, Benn Sheridan & Julie Leenane

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Once the dust has settled on a public inquiry, corporate participants may find themselves facing difficult questions: what is the status of the evidence disclosed during the inquiry?  And how far can this evidence be used to inform subsequent civil proceedings in which they may be implicated?

An answer to the second of these two questions may be found in an unexpected location: the Supreme Court’s decision in Evans v Barclays [2025] UKSC 48, a case which originated in the Competition Appeal Tribunal.

OVERVIEW OF THE RULES OF EVIDENCE IN PUBLIC INQUIRIES

Readers of this note may already be familiar with the rules of evidence in a public inquiry, which are set out in ss17-23 of the Inquiries Act 2005 (the “2005 Act”).  These sections give the inquiry chair a wide discretion over admitting relevant documents, and extensive powers to compel the production of documents where necessary.

Broadly, provided the inquiry chair acts fairly and efficiently, the chair may direct the procedure and conduct of the inquiry as they see fit (s17).  This is, however, subject to the default position that inquiry proceedings and the evidence to the inquiry are public (s18).

This presumption is balanced by the chair’s power to restrict public access to the inquiry and documents arising where necessary for reasons such as national security, personal safety, privacy, commercial confidentiality, economic harm, or the effective conduct of the inquiry.

In such cases, the chair’s powers are extensive.  They include an ability to restrict public access to the inquiry (s19(1)), to restrict disclosure or publication of inquiry evidence and documents (s19(2)), and a corollary power to require, by service of a notice, a person’s attendance and document production, which the inquiry chair may make subject to express undertakings (s21).

COLLATERAL USE OF EVIDENCE DISCLOSED IN A PUBLIC INQUIRY IN SUBSEQUENT PROCEEDINGS

Once an inquiry is finished, the availability for use in subsequent proceedings of documents made available to the inquiry will vary depending on any restrictions on use imposed by:

1. restrictions on use imposed while the inquiry was in session under s19;
2. public law principles and their effect on documents produced by a s21 order;
3. the Civil Procedure Rules and the Hunter

The section 19 restriction

Section 19 confers the most powerful barrier to collateral use of documents.  Where a document has been restricted from public access under s19, that restriction continues indefinitely, unless the notice or order itself provides for a point in time when the document shall become public, or the restriction is otherwise varied or revoked (s20(5)).  The effect is that restrictions can outlast the inquiry unless expressly time‑limited or later altered.

The breadth of this rule was recently tested in Lawrence v Associated Newspapers [2024] 1 W.L.R. 3669.  Three features of the reasoning of Nicklin J are worth emphasising:

1. The court will not permit the use in subsequent litigation of documents which have been provided or obtained in breach of a restriction order without the relevant restriction order being varied or revoked pursuant to section 20.  To do so would be an abuse of process: Lawrence [298].
2. The court has no power, equivalent to CPR 31.22(1)(b), to permit the use of documents provided in breach of a restriction order retrospectively or at all.  That power lies with the inquiry chair or, if the inquiry has finished, with the minister: Lawrence at [279].
3. Where a document is not expressly listed in a final restriction order made upon the conclusion of an inquiry, the court will consider the purpose and effect of the order.  If, so construed, evidence falls within the scope of the purpose of the order, then it may be protected by s19 regardless that it is not expressly referred to in the order.

Public law principles and documents obtained under s21

Where a document is not expressly or impliedly subject to a restriction under s19, its use in subsequent proceedings may nonetheless be limited depending on the circumstances in which it came before the inquiry, including if it was obtained by a s21 notice.

In these circumstances, it is an established public law principle (see, for example, Taylor v Director of SFO [1999] 2 A.C. 177) that documents should not be used for purposes other than those for which the powers conferred.  This flows from the significant interference with the disclosing party’s rights which compelling the production of documents represents.  This is matched by a corresponding limitation on use thereafter.  Collateral use of documents in these circumstances is an abuse of process.

Other categories of documents

Where documents provided to the inquiry are neither subject to an s19 restriction nor were obtained by way of a production order under s21, then the starting point remains that even though the documents is in the public domain, it may be used only for the purpose for which it was disclosed, and not in subsequent court proceedings.  This is the effect of the express undertaking contained in CPR 31.22(1).

However, the position is different if the document has (i) been read to or by the court; referred to at a hearing which has been held in public; the court gives permission; or the party who disclosed the document and the person to whom the document belongs agree.  Then there are few restrictions on the collateral use of the document – save for the court’s inherent power to prevent misuse of its procedure in a way which, though not inconsistent with the literal application of the CPR, would be manifestly unfair to a party to litigation.  This is the Hunter jurisdiction: Hunter v Chief Constable of the West Midlands Police [1982] A.C. 529, 536; see also the summary in Lawrence at [280].

WHAT IS THE EFFECT OF AN INQUIRY’S REPORT ON THE FINDINGS OF A SUBSEQUENT TRIBUNAL?

The recent Supreme Court decision in Evans has brought renewed attention to the rule in Hollington v Hewthorn [1943] KB 587.  This is the rule that findings of fact or of opinion in one investigation or set of proceedings, are generally not admissible to prove the facts in issue in a subsequent set of proceedings.

The Supreme Court in Evans held that this rule applies not only to the civil and criminal courts, but (contrary to previous appellate authority) to the Competition Appeal Tribunal (“CAT”).

The widening of the scope of the rule to the CAT might be thought to benefit inquiry participants: is it now arguable that a public inquiry’s findings of fact are similarly excluded by the rule?

In our view, whilst the Supreme Court in Evans did not explicitly consider opinion evidence from public inquiries, the judgment was wide ranging and set out principles of law which when applied render the findings of facts and opinion expressed in a public inquiry inadmissible in subsequent proceedings.  The following paragraphs in Evans appears to be unequivocal:

“[155] The reasons for treating findings made by an earlier decision-maker as inadmissible do not depend upon the capacity in which that person was acting. They apply to anyone who has previously expressed an opinion about what conclusions should be drawn from factual evidence. The rule is an aspect of the general exclusion of opinion evidence. The main exception is for expert evidence adduced in proceedings. Even then, only opinions on matters within the scope of the relevant expertise are admissible, and not opinions on the issues of law or fact which the court or tribunal has to decide.”

The caveat to that approach is that a report or judgment from a previous decision maker might be admissible at an interlocutory stage of proceedings.  This is not because the report is evidence itself, but because it can indicate at an interlocutory stage what evidence may be heard at the subsequent trial:

“(b) Interlocutory proceedings

“158. The argument that counsel for Mr Evans put at the forefront of their submissions on admissibility is that, even if the rule in Hollington v Hewthorn or the principle underlying it would apply at a trial of proceedings before the Tribunal, it does not (and would not in the High Court) preclude reliance on findings made by another decision-maker for the purpose of defeating a strike-out or summary judgment application or otherwise demonstrating the strength of claims at an interlocutory stage. In support of this argument, reliance was placed on cases holding that a party could rely on findings of another court for the purpose of demonstrating that there was a serious issue to be tried: see JSC Aeroflot Russian Airlines v Berezovsky [2013] EWCA Civ 784; [2013] 2 Lloyd’s Rep 242, paras 115-116 ; Sabbagh v Khoury [2014] EWHC 3233 (Comm), paras 202-207 ; Tulip Trading Ltd v Bitcoin Association for BSV [2023] EWHC 2437 (Ch), paras 17-57. In the last of these cases, at para 40, Mellor J concluded from the earlier authorities that:

“there is a limited exception to the rule in Hollington v Hewthorn which is applicable in situations where the case is at a preparatory stage yet the court has to consider what evidence at trial there might be. … [M]aterial (inadmissible at trial) can assist in identifying the evidence which can reasonably be expected to be available at trial, to which a court is entitled to have regard at the interlocutory stage.”

“159.  We endorse this analysis save only to observe that reliance on findings of another decision-maker for the purpose of identifying evidence which can reasonably be expected to be available at trial is not inconsistent with the rule in Hollington v Hewthorn and is therefore not strictly an exception to it. Likewise, it is not inconsistent with the principle underlying that case to rely on prior judgments or reports in so far as they record evidence of relevant facts: see eg Rogers v Hoyle, p 307 , para 49. It is only in so far as such material contains opinions on matters of fact (as opposed to recording evidence) that the material is inadmissible (unless it qualifies as expert evidence).”

If Evans is followed to its logical conclusion, then even if the evidence from an inquiry may (save in the circumstances discussed above) be admissible, the report itself should be inadmissible, unless it is treated as a species of opinion evidence.

A note of caution: there is a decision of the Administrative Court which seems to conflict with Evans but which was not considered by the Supreme Court.  In Secretary of State for Education and Skills v Mairs [2005] I.C.R. 1714 which dealt with the effect of the report of a statutory inquiry on subsequent findings by the Care Standards Tribunal, Leveson J held that a statutory inquiry was not a body which was “judicial in the relevant sense”; the report which an inquiry produced was “clearly admissible both as to the facts and as to … conclusions”: Mairs at [36]-[37].

However, elements of the rule in Hollington still echo through the judgment: though the “views expressed … will be highly persuasive and will require careful consideration”, the Care Standards Tribunal in Mairs was not bound to follow them, nor “inhibited in attaching greater weight to certain features … than did the tribunal”.

In other words, Mairs is authority for the proposition that although a tribunal may be entitled to admit an inquiry report in evidence, the final decision will be for the tribunal alone: an inquiry’s report (like any other item of admissible evidence) is open to robust scrutiny and testing in the adversarial system.

In our view, to the extent that they are in tension on the application of the rule in Hollington v Hawthorn to public inquiry reports, the Supreme Court judgment in Evans should be preferred to Mairs.  In Evans the Court consider the rule in its widest application across different jurisdictions.  It is also a judgment of the Supreme Court, and not the Administrative Court.  Mairs should be taken to be authority for the limited proposition that evidence heard in an inquiry might be admissible in subsequent proceedings, subject to procedural safeguards in the CPR.

In the context of subsequent criminal proceedings, we consider it is even more unlikely that a criminal court would be minded to admit the opinion of a public inquiry.  Opinion evidence is only admissible where it is expert opinion evidence on matters outside the ordinary understanding and experience of a jury, and then it must be admitted in accordance with Criminal Procedure Rule 19.4 (disclosure of materials relied upon, experience and skills, conflicts etc).  It is hard to see how the opinion of a public inquiry, however authoritative it may be, would be overcome the test of admissibility in a criminal court.

Consideration should also be  given to the fact that public inquiries admit hearsay evidence which is inadmissible in the criminal court, operate to the civil standard and burden of proof and exercise strict limits on the extent to which a Core Participant can cross-examine and call their own evidence.  In other words, the procedure adopted in a public inquiry is deliberately not adversarial, but this must affect the fairness of admitting its findings or opinions in any proceedings which are adversarial, including trial by jury.

CONCLUSION

To recap then, in our view, the collateral use of evidence heard by a public inquiry in subsequent High Court proceedings is permissible subject to strict, inflexible controls depending on whether s19 or 21 are engaged.  Other documents disclosed to Core Participants may be admissible in subsequent civil proceedings subject to CPR 31.22 and the Hunter jurisdiction.

The opinion evidence in inquiry reports as to the facts found, culpability of Core Participants and alike are generally inadmissible on the basis of the reasoning in Evans.  This rule applies to subsequent civil and criminal proceedings.  Where a party seeks to rely upon an inquiry report at an interlocutory stage as an indication of the evidence that may be available (eg at summary judgment), then this may be permitted subject to the jurisdiction of the subsequent court.

Tim Green KC
Benn Sheridan
Julie Leenane
4 March 2026

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