Ryan Halliday, R (on the application of) v The Parole Board for England and Wales

For judicial review of a Parole Board decision, a material mistake of fact requires an existing factual mistake, an established and objectively verifiable fact, no responsibility for the mistake on the claimant’s part, and material influence on the reasoning. A rationality challenge may succeed where the outcome was not reasonably open to the decision-maker or where the reasoning contains a demonstrable evidential, logical or methodological flaw. In cases concerning detention and liberty, the court must apply utmost scrutiny while respecting the Parole Board’s specialist expertise. A mistake concerning matters which the statutory public-protection test requires the Board to consider is ordinarily material where the Board expressly placed particular weight on it.

The claimant, a serving prisoner, challenged the Parole Board’s refusal to direct his release and its decision on reconsideration upholding that refusal. The challenges alleged material mistakes of fact and irrationality. The Board had wrongly proceeded on the basis that he had committed serious offences while on licence and had relied on custodial misconduct and intelligence which were not established. On reconsideration, the Board accepted one mistake but concluded that it was immaterial. The central issues were whether the mistakes satisfied the judicial-review test and whether the Decision or Reconsideration was unreasonable.

1. Decision and Reconsideration quashed. The court reviewed both decisions because they were inextricably linked.
2. Under E v Secretary of State for the Home Department [2004] EWCA Civ 49, a mistake-of-fact challenge requires: a mistake concerning an existing fact; an established, uncontentious and objectively verifiable fact; no responsibility for the mistake on the claimant’s part; and material, though not necessarily decisive, influence on the reasoning. The approach in R (Kitto) v Parole Board [2003] EWHC 2774 (Admin) supported quashing where the Board had taken account of a risk which did not exist.
3. The Decision contained two clear factual mistakes. It treated the claimant as having committed serious offences while on licence, although he had not, and relied on custodial behaviour and security information despite the relevant adjudication having been overturned and the alleged police intelligence lacking evidential support.
4. The mistakes were material. The Board expressly stated that it placed particular weight on them. They also concerned matters which section 237A(5)(c), (d) and (e) of the Criminal Justice Act 2003 required it to take into account.
5. Rationality, more accurately described as unreasonableness, includes both an outcome not reasonably open to the public authority and a decision reached through a demonstrable flaw in reasoning. The court adopted the clarification in R (Williams) v Parole Board [2025] EWHC 3183 that the issue is whether the conclusion was reasonably available in light of the evidence, rather than whether it was entailed by that evidence.
6. Applying utmost scrutiny in a detention and liberty case, the Decision was unreasonable because it gave particular weight to facts which were false or unsupported. It was also illogical to reject psychological evidence by relying on intelligence which the Board itself said was unsupported and to which it would attach no weight.
7. The Reconsideration was independently unreasonable. Its conclusion that the acknowledged mistake was immaterial contradicted the Decision’s express statement that the matter had attracted particular weight and itself repeated the material factual error. The matter was remitted to the Parole Board for a new review, to be conducted by oral hearing and expedited within its existing framework. No costs order was made against the Board.

This was a first-instance judicial review. The Parole Board had refused release on 28 July 2025 and upheld that decision on reconsideration on 17 September 2025. The High Court quashed both decisions and remitted the matter to the Parole Board.