“Thou shalt not kill. And if you do…. thou shalt not receive money”

G4S Health Services (UK) Ltd and others v Lewis‑Ranwell [2026] UKSC 2: illegality, insanity and coherence after Patel

Pankaj Madan of 12KBW explains why the Supreme Court departed from the Court of Appeal and how the Patel v Mirza framework was central.  The piece offers a practical checklist for solicitors, identifies which heads of loss are closed off, and points to routes that may still be open.

---

The Supreme Court in a 55-page judgment has held that the common law defence of illegality bars a claimant found not guilty by reason of insanity from recovering civil damages that are the consequence of his unlawful killings and the lawful detention that followed. Applying the Patel v Mirza framework, the Court concluded that permitting recovery would create damaging incoherence in the law and undermine public confidence. Unlawful killing never pays, even where the claimant is not criminally responsible by reason of insanity.

---

The facts and the journey to the Supreme Court

Mr Lewis‑Ranwell, suffering from paranoid schizophrenia, killed three elderly men during a psychotic episode in February 2019. He wrongly believed them to be paedophiles. At his criminal trial he was found not guilty of murder by reason of insanity and made the subject of a hospital order with restrictions under sections 37 and 41 of the Mental Health Act 1983. The jury did not convict of manslaughter by reason of diminished responsibility. A verdict of not guilty by reason of insanity therefore does not convict of a criminal offence. Instead, a hospital order may be imposed to keep the public safe.

Mr Lewis-Ranwell then sued G4S Health Services, Devon Partnership NHS Trust and Devon County Council, alleging negligent failures to assess and divert him for treatment earlier. He had committed more minor offences first and an assumption was made that non-negligent diagnosis and intervention would have prevented him from going on and committing the killing of the three men. Mr Lewis-Ranwell therefore claimed extensive damages. The defendants sought to strike out the claim on the basis of illegality. Garnham J refused. A Court of Appeal majority dismissed the defendants’ appeals. The Supreme Court granted permission and has now allowed the appeals.

The issues

1. Was the illegality defence engaged where the claimant’s underlying acts are unlawful killings but he is not criminally responsible by reason of insanity?
2. If engaged, should the defence bar the claim in whole or in part?

The Supreme Court answered both questions in the defendants’ favour. The defence barred the whole claim.

The decision in brief

1. Threshold: illegality is engaged

Although there is no conviction, the claimant’s conduct was unlawful in the sense that it engaged the interests of the state and the public.  He committed unlawful homicides and was lawfully detained to protect the public. The absence of criminal responsibility did not prevent the illegality doctrine from applying. The Court rejected the idea that the insanity versus diminished‑responsibility dividing line in criminal law should control the civil defence.

2. The Patel v Mirza analysis

The Court applied Lord Toulson’s trio:

• Purpose of the prohibition: the fundamental prohibition against taking human life protects life, deters killing and marks societal condemnation. Allowing a negligence claim to recoup the consequences of unlawful killings would cut against those aims and fracture legal coherence.
• Countervailing policies: there is a public interest in accountability for negligent services and in improving mental‑health care. But those aims can be pursued by other means such as inquests and inquiries, and they do not outweigh the coherence and public‑confidence considerations here.
• Proportionality: the killings were of the utmost gravity and were central to every head of loss claimed. Denial of the claim is proportionate.

3. Consequences for heads of loss

• Losses flowing from detention and criminal process: Irrecoverable under the narrower rule in Gray v Thames Trains because they are consequences of a lawful disposal ordered in response to the killings.
• Other losses said to flow from the killings: Irrecoverable under the wider rule in Gray because they arise from the claimant’s own unlawful acts, including loss of earnings after detention, reputational harm and similar consequences.
• Indemnity for civil liability to victims: Contrary to public policy and also vulnerable on duty, remoteness and causation. Allowing a killer to recover an indemnity for his batteries would bring the law into disrepute.

Why the Supreme Court disagreed with the Court of Appeal majority

The majority below treated the insanity verdict as a good reason to disapply illegality, reasoning that the claimant lacked moral culpability and that humane opinion would regard him as a victim. The Supreme Court disagreed on principled grounds:

1. Coherence, not culpability, is the test. The central rationale since Patel is the integrity of the legal system. The distinction between insanity and diminished responsibility reflects a spectrum of mental disorder in the criminal law. It should not control the civil law’s illegality threshold where the question is whether allowing the claim would make the law give with one hand and take with the other.
2. Consistency with Gray and Henderson. Those cases are Patel‑compliant policy decisions about maintaining consistency between criminal and civil outcomes. They do not turn on degrees of personal responsibility, and their logic applies where killings are unlawful although the claimant is not criminally responsible.
3. Public confidence and distributional fairness. Compensating the claimant for the consequences of his unlawful killings, often from public funds, would undermine public confidence. The public would reasonably see incoherence in paying damages for the very detention that exists to protect them from the risk exposed by the killings.
4. Alignment with comparative authority. The outcome accords with the predominant Commonwealth approach, notably Presland in New South Wales (Aus.) and Ellis in New Zealand, which emphasise public‑policy limits on recovering the consequences of unlawful killings even in insanity cases.

The law of illegality after G4S v Lewis‑Ranwell. A solicitor’s brief guide

A. Threshold question

Ask first whether the claimant’s own conduct that underpins the claim engages the public interest as unlawful in the Patel sense. That includes criminal offences and serious wrongs that are not punished because of insanity, where the conduct nevertheless triggers state interests like public protection. If yes, proceed to the Patel trio.

B. Apply the Patel trio per Lord Toulson

1. Purpose of the prohibition. Identify the policy of the transgressed rule and whether allowing the claim would erode that policy or create inconsistency. For unlawful killing, deterrence, condemnation and public protection carry great weight.
2. Countervailing policies. Weigh any competing policy, such as professional accountability or compensation of the blamelessly mentally ill person.
3. Proportionality. Assess seriousness, centrality to the losses claimed, intentionality, and relative culpability. In homicide cases, the scale and centrality will normally make a bar proportionate.

C. Heads of loss: what is typically barred or not barred

Barred in light of this decision

• Loss of liberty and amenity during detention ordered in response to the unlawful act.
• Post‑detention loss of earnings where the total loss flows from the unlawful killing and ensuing detention.
• Reputational harm, guilt and remorse said to flow from the killings.
• Indemnities against civil claims by victims or their families.

Potentially not barred

• Losses not causally dependent on the unlawful act, proved to have a separate, lawful causal chain, although these are uncommon on such facts.
• Claims under the Human Rights Act 1998, which are not defeated by illegality as such, though quantum and causation remain live.

D. A five‑step apply‑in‑conference checklist

1. Establish each pleaded head of loss and link it to its causal source.
2. Establish the threshold by explaining why the conduct engages the public interest even without a conviction because of insanity.
3. Run the Patel trio, ending with a proportionate response analysis.
4. Classify each head under the Gray narrower rule, the wider rule, or outside both, with short reasons.
5. Flag alternate routes such as HRA claims and non‑damages mechanisms including inquests or investigations.

Practical implications for personal injury and clinical negligence practice

• The suggested insanity exception is closed. Insanity does not create a carve‑out from illegality for claims that attempt to shift the consequences of unlawful killings onto healthcare providers or public authorities. Expect robust strike‑out applications directed at detention-linked heads of loss, and heads of loss linked to unlawful killing.
• Plead with precision on causation. Claimants must show a genuinely independent causal pathway for any head of loss they say survives illegality. Defendants should press for head‑by‑head analysis and rely on the twin Gray rules.
• Remember parallel liabilities. The claimant remains liable in the tort of battery to victims’ estates, and courts will not permit indemnities that would transfer that civil responsibility to negligent third parties.
• Public law and HRA routes. Where systemic failings are at issue, public law remedies and HRA claims may remain available, but awards and causation will be closely scrutinised.

Conclusion

The judgment recentres illegality on legal coherence rather than moral blameworthiness. The message for practitioners is clear. In homicide cases, whether the criminal verdict is diminished responsibility or insanity, civil courts will not compensate the perpetrator for the consequences of the killing even if potentially the perpetrator was a victim themselves of negligence. The Patel framework remains the analytic tool, but the outcome in this class of case will rarely be in doubt.

---

About the author

Pankaj Madan is a Barrister specialising in catastrophic injury and brain injury from the subtle to the catastrophic, and severe pain cases. He acts for both Claimants and Defendants. He is the author of 3 leading texts; on Subtle Brain Injury; Chronic Pain and a recent book on Catastrophic Brain Injury. He practises from Exchange Chambers and 12 King’s Bench Walk. He is President-Elect of the Royal Society of Medicine, Pain Section Council. He is Legal 500 PI Junior of the year 2025 and is a co-opted member of the PIBA Executive Committee. All views expressed are personal.

---

Disclaimer and Exclusion of Liability

This article is provided for general information purposes only. It does not constitute legal advice and should not be relied upon as such. No responsibility or liability is accepted for any loss or damage arising from reliance on the contents of this article. Readers are strongly advised to seek appropriate, legal advice before taking any action or making any decisions based on the information provided herein. The author and publisher expressly exclude all liability for actions taken or not taken in reliance on this article.