Supreme Court unanimously decides woman’s claim of negligence by her Trust should be barred by the illegality defence 12/3/2020 Investigations and Reviews A woman who killed her own mother while experiencing a psychotic episode has had her pursuit of damages ended by the Supreme Court. Ms Henderson, who suffers from paranoid schizophrenia or schizoaffective disorder, was under the care of a community mental health team in August 2010, which was managed and operated by Dorset Healthcare University NHS Foundation Trust. On or around 13 August 2010, Ms Henderson’s condition began to deteriorate, two weeks before she stabbed her mother to death whilst experiencing a serious psychotic episode. Ms Henderson, who remains in hospital, was convicted of manslaughter by reason of diminished responsibility and received a hospital order, under section 37, and an unlimited restriction order under section 41 of the Mental Health Act 1983. Ms Henderson brought a negligence claim against the Trust, seeking damages for personal injury, and other loss and damage, on the basis that had she been provided with adequate care and treatment by the Trust, the death of her mother could have been avoided and she would not have been detained indefinitely thereafter. Damages were claimed for pain suffering and loss of amenity, damages for loss of liberty, and special damages, including future losses for psychotherapeutic treatment. The Trust admitted liability for its negligent failure to return Ms Henderson to hospital when her psychiatric condition deteriorated and it accepted that, if it had done this, the death of Ms Henderson’s mother would not have taken place. The Trust disputed that the claimant was entitled to any damages by reason of illegality and/or public policy grounds. The case reached the Supreme Court, who were asked to consider whether the common law doctrine of illegality precludes a claimant who commits a criminal offence, during a serious psychotic episode, from recovering damages for loss arising out of that offence, which she would not have committed but for the defendant’s negligence. The Supreme Court unanimously held that Ms Henderson’s claim against the Trust was barred by the illegality defence. Janet Hawthorne, Legal Director of Iodem Limited, said: “The court’s analysis of the issues raised in this case has important implications for those individuals seeking damages in cases involving illegal conduct where they have lacked responsibility for their actions. “The Judges clearly rejected the idea that a civil court should have to assess whether or not a claimant has a significant degree of personal responsibility for their crime, on the basis that this would create a clear risk of inconsistent decisions between the criminal and civil courts.” Mrs. Hawthorne concluded: “The Court also recognised the public interest in relation to the allocation of NHS resources in such proceedings. “This must be a victory for common sense.”