Lewis-Ranwell v G4S Health Services (UK) Ltd and others No 2 [2026] UKSC 2

A man who killed three people during a psychotic episode was found not guilty of murder by reason of insanity. He sued healthcare providers for negligence, claiming damages for his detention and other losses. The Supreme Court held that the illegality defence barred his civil claim despite his lack of criminal responsibility, as allowing recovery would damage the integrity of the legal system.

Facts

Alexander Lewis-Ranwell, who had a history of schizophrenia, was arrested twice in February 2019 and released despite exhibiting violent and erratic behaviour indicative of serious mental illness. During both periods of detention, mental health professionals from G4S Health Services, Devon Partnership NHS Trust, and Devon County Council failed to arrange adequate mental health assessments or detention under the Mental Health Act 1983. Following his second release, while experiencing a severe psychotic episode, he killed three elderly men in the delusional belief they were paedophiles. At his criminal trial, he was found not guilty of murder by reason of insanity and was made subject to a hospital order with restrictions under sections 37 and 41 of the Mental Health Act.

The Civil Claim

The claimant brought civil proceedings against the healthcare providers alleging negligence in failing to provide adequate care and mental health assessment. He sought damages for loss of liberty during detention, loss of earnings, loss of reputation, psychiatric injury, and an indemnity against claims from his victims’ families.

Issues

The central issues before the Supreme Court were:

• Whether the defence of illegality is engaged by a civil claim in negligence where the claimant was found not guilty of murder by reason of insanity
• If engaged, whether the illegality defence bars the claimant’s claim in whole or in part

Judgment

The Threshold Question

The Supreme Court held that the claimant’s conduct was unlawful so as to engage the illegality defence, notwithstanding the verdict of not guilty by reason of insanity. Lord Hodge and Lord Lloyd-Jones, delivering the unanimous judgment, stated:

Killing another human being without lawful justification breaches a fundamental moral rule in our society – you shall not kill. This is so even when the person who has killed bears no criminal responsibility for his actions.

The Court rejected the argument that the distinction between diminished responsibility and insanity in criminal law should determine the availability of the illegality defence in civil proceedings:

The difference between those who are criminally responsible for their acts, notwithstanding their diminished responsibility, and those who are not because they do not know that what they are doing is morally or legally wrong is between positions on a spectrum of the severity of mental illness. That difference is not critical to the applicability of the policy considerations required under Patel.

The Patel Assessment

Applying the trio of considerations from Patel v Mirza [2017] AC 467, the Court conducted a structured analysis:

Stage (a): Underlying Purpose of the Prohibition

The prohibition against killing serves to preserve life and promote respect for its sanctity. The Court identified multiple inconsistencies that would damage the integrity of the legal system if the claim were allowed:

To allow the claimant to recover compensation for his detention would be wholly inconsistent with the rule requiring his detention. It would be inconsistent for a civil court to order the payment of compensation to the claimant for the consequences of his lawful detention ordered by a criminal court.

The Court also noted that the claimant remains liable in tort for battery to his victims’ estates, creating further incoherence if he could shift that liability to the defendants.

Stage (b): Other Relevant Public Policies

While acknowledging the general public interest in adjudicating civil wrongs, the Court found these considerations did not outweigh the need to maintain legal consistency. Alternative procedures such as inquests exist for examining standards of care.

Stage (c): Proportionality

The Court concluded that denial of the claim was proportionate given the utmost seriousness of the conduct, its centrality to all heads of loss claimed, and its role as the effective cause of such loss.

Implications

This judgment significantly develops the law on the illegality defence by extending its application to cases where the claimant lacks criminal responsibility. The decision establishes that:

• The distinction between diminished responsibility and insanity under criminal law does not determine the scope of the illegality defence in civil proceedings
• The underlying rationale of the defence – maintaining coherence in the legal system – applies equally where conduct is unlawful even if not criminally punishable
• Public confidence in the integrity of the legal system requires that a person who has unlawfully killed cannot recover compensation for the consequences of that killing, regardless of their mental state at the time

The judgment affirms and extends the principles established in Gray v Thames Trains Ltd [2009] AC 1339 and Henderson v Dorset Healthcare University NHS Foundation Trust [2021] AC 563, confirming their compatibility with the structured approach to illegality adopted in Patel v Mirza.

Verdict: Appeal allowed. The illegality defence bars the claimant’s civil claim in negligence in its entirety. The claimant cannot recover damages for loss of liberty, loss of earnings, loss of reputation, or any other heads of loss claimed, nor obtain an indemnity against claims from his victims’ families.

Source: Lewis-Ranwell v G4S Health Services (UK) Ltd and others No 2 (UKSC/2024/0040)