Claim barred by illegality defence

Henderson (A Protected Party by Her Litigation Friend, The Official Solicitor) v Dorset Healthcare University NHS Foundation Trust [2020] UKSC 43

A patient diagnosed with a serious mental illness who had killed her mother during a severe psychotic episode was not entitled to recover damages from an NHS Trust despite the negligent failure of its staff to return her to hospital before she had a chance to carry out the killing. Applying the public policy approach in Gray v Thames Trains Ltd [2009] UKHL 33, her claim was precluded by the doctrine of ex turpi causa, also known as the illegality defence, which prevented a claimant from being compensated for losses suffered as a result of his or her own criminal act.