Illegality defence upheld

The court unanimously dismissed Ecila Henderson’s appeal, confirming the illegality defence applied, in Henderson v Dorset Healthcare University NHS Foundation Trust [2020] UKSC 43, [2020] All ER (D) 124 (Oct).

Henderson was receiving outpatient treatment for paranoid schizophrenia from Dorset Healthcare, when her condition grew worse. It was common ground that the steps taken by Dorset to help her were inadequate. Sadly, during a psychotic episode, Henderson stabbed her own mother to death. She pleaded guilty to manslaughter by way of diminished responsibility and has been subject to a hospital order under the Mental Health Act since this tragic event. The judge at her criminal trial said there was no suggestion that she should be seen as bearing responsibility for what she did.

She brought a civil claim against Dorset Healthcare, on the basis she would not have committed this tragic act but for their negligence. However, the defendant countered with the defence of illegality, or ex turpi causa, since the claim arose from the claimant’s illegal conduct.

The Supreme Court held that a range of public policy considerations should be weighed when considering the illegality defence, particularly the public policy in favour of the consistency of the law as a whole.

Delivering his judgment, Lord Hamblen said: ‘To allow recovery would be to attribute responsibility for that criminal act not, as determined by the criminal law, to the criminal but to someone else, namely the tortious defendant.

‘There is a contradiction between the law’s treatment of conduct as criminal and the acceptance that such conduct should give rise to a civil right of reimbursement. The criminal under the criminal law becomes the victim under tort law.’

Mark Ashley, partner at DAC Beachcroft, which acted for Dorset Healthcare, said: ‘If a claimant is injured during, or as a consequence of, their own serious criminal act that claimant will in general not be permitted to receive compensation from the person who injured them. This applies even if that claimant has relatively little personal responsibility for the criminal offence (for instance because of mental illness).’