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Legal case

Ex turpi causa — Supreme Court decision

A reminder about the considerations the court will apply when dealing with a defence of ex turpi causa

Elica Henderson (A protected party, by her Litigation Friend, The Official Solicitor) (Appellant) v Dorset Healthcare University NHS Foundation Trust (Respondent) [2020] UKSC 43

Executive Summary

The Supreme Court has held, in dismissing the appellant’s appeal and upholding the respondent’s defence of ex turpi causa, that damages for loss of liberty whilst hospitalised cannot be recovered as the losses resulted from a criminal court’s sentence. The appellant was also barred from recovering damages for post-traumatic stress disorder as that condition was a consequence of the unlawful killing of the appellant’s mother.

The facts

The appellant, who was suffering from paranoid schizophrenia or schizoaffective disorder, stabbed her mother to death during a psychotic episode. The appellant had pleaded guilty to manslaughter by reason of diminished responsibility and thus was guilty of an unlawful act. It had been common ground between the parties throughout that the act would not have occurred but for the respondent’s breach of duty in failing to respond to the appellant’s deteriorating mental health.

Based on the conclusions of an independent investigation, the appellant subsequently brought a civil claim for losses arising from her detention, damages for her post-traumatic stress disorder consequent on the killing of her mother and the loss of gains from her late mother’s Will. The issue was whether, the respondent, having admitted liability for the appellant’s mental health treatment, should be liable for the losses claimed or whether the public policy doctrine of illegality precluded her from succeeding in those claims and recovering damages arising out of her own unlawful acts.

The appellant, having had her claim dismissed at first instance, and that decision being upheld by the Court of Appeal, was granted permission to appeal to the Supreme Court.

Supreme Court

The Supreme Court had to determine:

  • Whether the decision in Gray v Thames Trains Ltd [2009] UKHL 33 (“Gray”) could be distinguished; and
  • If not, whether the court should depart from Gray in light of the decision in Patel v Mirza [2016] UKSC 42 (“Patel”).

The defence pleaded ex turpi causa based on the appellant’s claim for damages arising from firstly, the sentence imposed by the criminal courts and, secondly, her criminal act of manslaughter.

In relation to the first consideration, the appellant had argued that Gray could be distinguished, as in that case, Gray had been found responsible for his unlawful act by the criminal courts. In the material case the criminal court had found there was no suggestion that the appellant could bear a significant responsibility for her criminal act. The Supreme Court rejected this argument because the crucial consideration in Gray was that the claimant had been found criminally responsible for his conduct, not the degree of personal responsibility which that reflected.

As to the second issue, in Patel the court held that the correct approach to a defence of illegality was to balance public policy considerations. The underlying policy question was, whether to allow recovery for something which is illegal would produce inconsistency and disharmony in the law and so cause damage to the integrity of the legal system. This was to be assessed by considering a trio of factors: -

  • the underlying purpose of the illegality in question, and whether that purpose would be enhanced by denying the claim; and
  • any other relevant public policy on which denying the claim may have an impact; and
  • whether denying the claim would be a proportionate response to the illegality.

Considering all of the above, the Supreme Court held, in dismissing the appeal, that the trio of considerations approach in Patel did not lead to a different outcome in this case and, as such, Gray was affirmed by the Supreme Court as being Patel compliant and should be applied and followed in similar cases.


This case, whilst no doubt a relief for defendants, serves as a reminder about the considerations the court will apply when dealing with a defence of ex turpi causa. It has been a long-established principle that damages in the civil courts ought not to be recovered as a consequence of a criminal act. As the Supreme Court stated in their judgment:

 “Although a claimant in Ms. Henderson’s position may be deterred from unlawful killing by being deprived of a civil right to compensation, there may well be a broader deterrent effect in a clear rule that unlawful killing never pays. Any such effect is important given the fundamental importance of the right to life”.

This decision not only prevents the opening of the floodgates for similar claims but will, no doubt, be welcomed by insurers and the NHS alike.