Ex Turpi Causa – Is Illegality Still a Good Defence in Civil Claims?

In this post, Dr David Sharpe QC considers the defence of illegality in the context of clinical negligence following the Supreme Court judgment in Ecila Henderson (A Protected Party, by her litigation friend, The Official Solicitor) (Appellant) v Dorset Healthcare University NHS Foundation Trust (Respondent) [2020] UKSC43.

The Issue

This appeal concerns the common law defence of illegality. The Supreme Court (‘UKSC’) considered whether the appellant, Ecila Henderson (‘EH’), could claim damages for loss she had suffered as a result of conviction for her mother’s manslaughter from the respondent, Dorset Healthcare University NHS Foundation Trust (‘DHT’).

Background Facts

EH had a long history of paranoid schizophrenia. In August 2010, she was under the care of DHT. On or around 13 August 2010, EH’s condition began to deteriorate. On 25 August 2010, she stabbed her mother to death whilst experiencing a serious psychotic episode.

EH was subsequently convicted of manslaughter by reason of diminished responsibility. In her criminal trial, the judge said that there was no suggestion that EH should be seen as bearing a significant degree of responsibility for what she had done. The judge sentenced EH to a hospital order under section 37 and an unlimited restriction order under section 41 of the Mental Health Act 1983. EH has remained in hospital ever since, and is not expected to be released for some time.

The Case before the High Court and Court of Appeal

EH brought a negligence claim against DHT, claiming damages for personal injury and other loss and damage under six heads: (i) damages for the depressive disorder and post-traumatic stress disorder; (ii) damages for loss of liberty; (iii) loss of amenity; (iv) £61,944 being the share in her mother’s estate which she did not inherit due to operation of the Forfeiture Act 1982; (v) cost of psychotherapy; (vi) cost of a care manager/support worker.

DHT admitted liability for its negligent failure to return EH to hospital when her psychiatric condition deteriorated. It accepted that, if it had done this, the tragic killing of EH’s mother would not have taken place. However, it argued that EH’s claim was barred for illegality, because the damages she claims result from: (i) the sentence imposed on her by the criminal court; and/or (ii) her own criminal act of manslaughter.

Similar claims for damages to those made by EH were held to be irrecoverable by the House of Lords in Gray v Thames Trains Ltd [2009] UKHL 33; [2009] AC 1339 (‘Gray’). The recoverability of the damages claimed was, therefore, ordered to be tried as a preliminary issue. The High Court judge determined the preliminary issue in favour of DHT, and the Court of Appeal dismissed EH’s appeal. Both the High Court and the Court of Appeal held that the facts of EH’s claim were materially identical to those in Gray, which was binding upon them.

The Legal Issues before UKSC

The appeal raised three questions (1) whether Gray could be distinguished and, if not, (2) whether it should be departed from, in particular in the light of the more recent Supreme Court decision concerning illegality in Patel v Mirza [2016] UKSC 42; [2017] AC 467 (‘Patel’), and (3) whether EH could recover damages.

Question 1 – Can Gray be Distinguished?

In Gray, the House of Lords held that Mr Gray’s negligence claim was barred by the defence of illegality because the damages he sought resulted from: (i) the sentence imposed on him by the criminal court; and/or (ii) his own criminal act of manslaughter. It was argued that Gray concerned a claimant with significant personal responsibility for his crime. In contrast, in EH’s criminal trial, the judge said that there was no suggestion that Ms Henderson should be seen as bearing a significant degree of responsibility for what she had done.

The UKSC rejected EH’s argument and held that Gray cannot be distinguished. The crucial consideration in Gray was that the claimant had been found to be criminally responsible for his conduct, not the degree of personal responsibility which that reflected. Lord Phillips reserved judgment in Gray on whether the illegality defence would apply to a case where the claimant did not bear significant personal responsibility for their crime, but this was not the view of the majority.

Question 2 – Should the Court depart from Gray given its judgment in Patel?

In Patel, the UKSC held that the proper approach to the illegality defence at common law was one based on a balancing of public policy considerations rather than a reliance-based approach. The majority held the underlying policy question to be whether allowing 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. In assessing whether the public interest would be harmed in that way, the court should consider a “trio of considerations”, namely: stage (i) the underlying purpose of the illegality in question, and whether that purpose would be enhanced by denying the claim; stage (ii) any other relevant public policy on which denying the claim may have an impact; and stage (iii) whether denying the claim would be a proportionate response to the illegality.

The argument advanced by EH was that the Court should depart from Gray on three grounds. The first ground was that the reasoning in Gray is incompatible with the approach to illegality adopted in Patel. The Court held, however, that the essential reasoning in Gray is consistent with Patel, and so remains good law. The second ground was that Gray should not apply where the claimant has no significant personal responsibility for the criminal act and/or there is no penal element in the sentence imposed on them by the criminal court. The Court rejected this argument because it would damage the integrity of the legal system with a convicted criminal under the criminal law becoming the victim under the civil law. The third ground was that EH’s claim would be allowed under the ‘trio of considerations’ approach in Patel. The Court confirmed that they should usually be capable of being addressed as a matter of argument and at a level of generality that does not make evidence necessary, that they involve a balancing between policy considerations arising under stages (a) and (b) and that stage (c) relates to proportionality and factors specific to the case rather than general policy considerations; The Court also held it is appropriate to give great weight to the policy considerations that a person should not be allowed to profit from his own wrongdoing and that the law should be coherent; Where the policy considerations come down firmly against denial of the claim it will not be necessary to consider stage (c) and proportionality; In terms of proportionality, both the centrality and the closeness of the causal link between the illegality and the claim will often be factors of particular importance.

Question 3 – Can EH recover damages for any of the heads of loss she has claimed?

EH cannot claim damages for loss of liberty or for loss of amenity during her detention in hospital because these heads of loss result from the sentence imposed on her by the criminal court. The other heads of loss cannot be recovered because they result from EH’s unlawful killing of her mother. The Court considered it was inappropriate to subvert the operation of the Forfeiture Act 1982, which prevented EH from recovering her full share of her mother’s estate.


This judgment entrenches the existing law and the illegality defence. Given that EH was held to have had minimal responsibility for the manslaughter and that DHT had admitted breach of duty in respect of its treatment failure it is perhaps surprising that the UKSC was not more open to distinguishing Gray on the facts. However, the judgment provides clarity and certainty with the caveat at [112] that there may be some exceptional, trivial or strict liability offences which do not engage the illegality defence. The judgment was primarily decided on consistency and public confidence principles. It is likely to attract professional and academic comment both by lawyers and mental health advocates.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s