Lewis-Ranwell v G4S Health Services (UK) Ltd and others

The illegality defence may bar a negligence claim arising from an intentional unlawful killing even where the claimant was found not guilty by reason of insanity. Criminal responsibility is not the threshold. Conduct engages the defence where its nature implicates the interests of the state or the public.

The court must apply the structured public-policy assessment in Patel v Mirza. It considers the purpose of the prohibition transgressed, countervailing policies and proportionality. Compensation for detention ordered to protect the public would contradict the legal basis for that detention. Compensation for other consequences of the killing, including an indemnity against victims’ claims, would impermissibly transfer civil responsibility for the claimant’s intentional torts. The distinction between diminished responsibility and insanity does not determine the civil illegality defence.

The respondent, while experiencing a severe psychotic episode, intentionally killed three strangers. A jury found him not guilty of murder by reason of insanity. The Crown Court consequently made a hospital order and restriction order under sections 37 and 41 of the Mental Health Act 1983, pursuant to section 5 of the Criminal Procedure (Insanity) Act 1964.

He alleged that healthcare and public-authority defendants had negligently failed to assess and treat him before the killings. He sought damages for psychiatric injury, detention, reputational loss, lost earnings, care and treatment, and an indemnity against claims by his victims or their families.

Garnham J dismissed applications to strike out the negligence claims: [2022] EWHC 1213 (QB). The Court of Appeal dismissed the defendants’ appeals by a majority, Andrews LJ dissenting: [2024] EWCA Civ 138. The Supreme Court had to decide whether the unlawful killings engaged the illegality defence and, if so, whether the defence barred some or all of the negligence claim.

1. Appeal allowed unanimously. Lord Hodge and Lord Lloyd-Jones gave the judgment, with which Lord Reed, Lady Rose and Lady Simler agreed. The intentional killing of three people was unlawful conduct sufficient to engage the illegality defence, although the claimant had been found not guilty by reason of insanity. The threshold is not confined to conduct attracting criminal responsibility. It includes conduct which engages the interests of the state or the public interest.

2. The criminal-law distinction between diminished responsibility and insanity did not govern the civil defence. Insanity removed criminal responsibility but did not justify the killings. The verdict established the actus reus of murder. On the evidence in this case, the claimant also intended to kill, although he did not appreciate that his conduct was wrong. His acts manifested a danger to the public and resulted in detention ordered for public protection.

3. The governing assessment was the structured approach in Patel v Mirza [2016] UKSC 42. The court considered: the purpose of the prohibition against killing; countervailing public policies; and whether denial of the claim was proportionate. The preservation of life, condemnation of unlawful killing, internal consistency of the law and public confidence strongly favoured denial.

4. Compensation for detention would contradict the criminal court’s mandatory and lawful order protecting the public. It fell within the narrower rule in Gray v Thames Trains Ltd [2009] UKHL 33. The remaining losses were caused by the claimant’s unlawful killings and fell within the wider rule. His insanity also provided no defence to civil liability in battery. Permitting an indemnity against victims’ claims would improperly shift responsibility for his intentional torts to the defendants and bring the law into disrepute.

5. The public interest in adjudicating civil wrongs and improving mental-healthcare standards carried some weight. Inquests and public inquiries could also examine systemic failings. Those considerations were greatly outweighed by the need for legal coherence. Denial was proportionate because the killings were of the utmost seriousness, central to every claimed loss and their effective cause.

6. All heads of loss in the negligence claims against the appellants were barred. The majority decision of the Court of Appeal was reversed. The claims against the Chief Constable and the claims under the European Convention and the Human Rights Act 1998 were not the subject of the appeal and could proceed.

1. United Kingdom Supreme Court: By a unanimous judgment, allowed the appellants’ appeal and held that every head of loss in the negligence claims against them was barred by illegality: [2026] UKSC 2 .
2. Court of Appeal: By a majority, dismissed the defendants’ appeals; Andrews LJ dissented: [2024] EWCA Civ 138 ; [2024] KB 745.
3. High Court, Queen’s Bench Division: Garnham J dismissed the applications to strike out the negligence claims or enter summary judgment: [2022] EWHC 1213 (QB) ; [2023] QB 229.