Public authorities win Supreme Court case over claim for negligence brought by man found not guilty of murder by reason of insanity

In Lewis-Ranwell v G4S Health Services (UK) Ltd and others [2026] UKSC 2 claimant Alexander Lewis-Ranwell, who is diagnosed with schizophrenia, brought civil proceedings against the defendants to recover compensation for the consequences of these killings.

On 10 February 2019, he attacked and killed three elderly men, Anthony Payne, Richard Carter and Roger Carter, in their own homes.

He did so in the course of a serious psychotic episode, under the delusional belief that they were paedophiles. He was arrested the following day after a further assault.

At his criminal trial, he was found not guilty of murder by reason of insanity.

“This means that it was accepted that he carried out the killings but was found not to be criminally responsible. In law, this plea is available if, due to mental disorder, the individual either did not know the nature of his acts or did not know that what he was doing was wrong,” the Supreme Court press summary noted.

The claimant was detained at Broadmoor Hospital where he remains under a hospital order and a restriction order.

The Supreme Court said that in the days before the killings, Lewis-Ranwell had been arrested and detained on two occasions for a suspected burglary and an assault on an elderly man.

“During each detention, he behaved erratically and violently and appeared mentally very unwell. He was seen by mental health practitioners. The need for mental health assessments was discussed but not arranged before he was released on bail.”

Lewis-Ranwell brought a claim for compensation against four defendants.

G4S Health Services (UK), the first defendant, is a private company with responsibility for provision of forensic medical services to persons in custody. This responsibility had been outsourced from the Chief Constable of Devon and Cornwall Police, the second defendant.

Devon Partnership NHS Trust, the third defendant, was responsible for assessing people with mental illnesses in the criminal justice system.

Devon County Council, the fourth defendant, was responsible for an emergency team of mental health practitioners who provided mental health assessments.

The claimant alleged that the four defendants were negligent in failing to provide him with adequate care or a mental health assessment.

“He alleges that, but for the alleged negligence, he would have been admitted to hospital and would not have killed the three men. Instead, he was released into the community in a psychotic state. He now seeks to recover damages for the consequences of the killings, including those arising from his compulsory detention, and an indemnity against any claims brought against him by the families of the men he killed,” the Supreme Court said.

The defendants, except the Chief Constable of Devon and Cornwall Police, issued applications to strike out the negligence claim on the ground that it was barred by the doctrine of illegality.

The trial judge dismissed the application, finding that the claim was not barred by the claimant’s illegal conduct and could proceed.

The three defendants appealed to the Court of Appeal, which dismissed the appeal by a majority, with Andrews LJ dissenting.

G4S Health Services, the council and the NHS trust appealed to the Supreme Court.

The three defendants now appeal to the Supreme Court.

The Supreme Court unanimously allowed the appeal, holding that the claimant was barred by the doctrine of illegality from bringing civil proceedings in negligence to recover compensation for the consequences of the killings.

Lord Hodge and Lord Lloyd-Jones gave the judgment, with which Lord Reed, Lady Rose and Lady Simler agreed.

Click here for the full judgment, which considered (i) the threshold question and (ii) an assessment of whether the defence should apply to the case at hand. In the latter respect the Supreme Court examined the purpose of the prohibition that had been transgressed (you shall not kill), other relevant public policies and the proportionality of denying a civil claim.