Illegality defence does not apply to insanity cases


In an important decision on the illegality defence, Selena Plowden QC represented the Claimant, defeating strike out applications.

On the morning of 10 February 2019, Alexander Lewis-Ranwell was released from custody at Barnstaple Police Station whilst acutely psychotic. That day, he went on to kill three men, who he delusionally believed were endangering the lives of young women.

At the murder trial Alexander was represented by Andrew Langdon QC of Guildhall Chambers. The jury found that Alexander was not guilty of murder by reason of insanity. At the conclusion of the trial, the jury passed a note to the judge, that read: “We the Jury have been concerned at the state of psychiatric health service provision in our county of Devon. Can we be reassured that the failings in care for ALR will be appropriately addressed following this trial?”.

Since the killings, Alexander has been compulsorily detained, first in prison, then in psychiatric facilities, where he remains.

Alexander is pursuing a claim in negligence and for breach of his European Convention rights against the police and three bodies involved in the provision of healthcare services whilst he was at Barnstaple Police Station.

Three of the four defendants applied to strike out the claim on the basis of the illegality defence / ex turpi causa. The strike out application was heard over two days by Garnham J. Judgment was handed down today, dismissing the Defendants’ applications on the basis that the illegality defence / ex turpi causa does not apply where a claimant has been found not guilty by reason of insanity. This is the first binding judgment on this issue.

A copy of the judgment is available here: Alexander Lewis-Ranwell v G4S Health Services (UK) Limited & Ors – Find case law (

Selena Plowden QC of Guildhall Chambers led Christopher Johnson of Doughty Street Chambers and was instructed by Chris Thorne and James Edmondson of Clarke Willmott.


Selena Plowden KC

Call: 1991 Silk: 2020

Related Practice Areas

Personal Injury

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