When might a defence based on the ex turpi or illegality principle be successful in a tort case? The ex turpi rule (or ex turpi causa non oritor actio, to give the principle its full name) is that no legal action based on illegality can succeed.

For many years, the courts adopted a flexible approach to the principle in tort cases, as the seriousness of the illegality could vary. A public conscience test was developed. In Tinsley v Milligan (1993), the House of Lords applied a test based on reliance: did the claimant have to rely on their own illegality in order to pursue their claim? If so, the claim would fail. Tinsley was a property rights case, though. Two recent decisions have examined how far the Tinsley principle applies to tort claims.

Gray v Thames Trains Ltd

The first case is the Court of Appeal decision in Gray v Thames Trains Ltd (2008). Mr Gray was a victim of the Ladbroke Grove rail crash in October 1999. Although he suffered fairly minor physical injuries, the accident had a significant psychological effect upon him – post-traumatic stress disorder (PTSD) with a marked depressive component. The defendants admitted liability.

Subsequently, on 19 August 2001, Mr Gray stabbed a stranger to death – an act which was completely out of keeping with his previous character. Mr Gray pleaded guilty to manslaughter on the grounds of diminished responsibility and was detained under the Mental Health Act 1983. He later claimed damages from the defendant train companies, including loss of earnings arising from the rail crash.

The defendants accepted they were liable for losses up to 19 August 2001. However, they denied liability for losses after that date on the grounds of the claimant’s illegal action. At trial, Mr Justice Flaux rejected Mr Gray’s claim. He ruled that a claimant breaches the ex turpi principle if their claim is closely connected to – or is inextricably bound up with – their own criminal or illegal conduct. This was the position in Mr Gray’s case.

The Court of Appeal reversed Mr Justice Flaux’s decision. It said that if Mr Gray had been convicted of an offence unconnected to the PTSD, the chain of causation would have been broken and the defendants would have had a defence. The key question was whether a claimant’s loss was so closely connected to – or inextricably bound up with – their criminal or illegal conduct that the court could not allow them to recover damages without appearing to condone their behaviour. If the manslaughter did not break the chain of causation between the tort and the loss of earnings, then any loss of earnings after 19 August 2001 was not inextricably bound up with Mr Gray’s illegal killing of the stranger.

The court accepted that Mr Gray would not have committed manslaughter if he had not suffered the PTSD caused by the tort. Consequently, the illegal act did not break the chain and Mr Gray was entitled to recover loss of earnings. The test in Tinsley was too narrow to apply to a case in tort: the Court of Appeal preferred a broader principle. The Court of Appeal distinguished two earlier Court of Appeal cases – Clunis and Worrall – on the grounds that the losses suffered in those cases were a direct result of crime, rather than a foreseeable result of a breach of duty of care owed by the defendant. Clunis and Worrall would certainly stop a claimant recovering losses caused by compulsory detention in prison or hospital. But neither decision had looked at the question of whether the loss of earnings was caused by a defendant’s negligence rather than a claimant’s commission of a criminal offence and subsequent imprisonment.

Corr v IBC Vehicles Ltd

After arguments had been heard in the Gray case, the House of Lords gave judgment in Corr v IBC Vehicles Ltd (2008). Although this was a suicide case, it raised questions that could be important in Gray. The Court of Appeal therefore invited the parties to make written submissions about the issues in the House of Lords’ decision.

In the Corr case, it was decided that the claimant’s widow was entitled to damages for loss of dependency, as her husband’s suicide did not break the chain of causation. The claimant had suffered serious injury at work and became severely depressed before committing suicide. The House of Lords unanimously decided that the claimant’s depression was a reasonably foreseeable consequence of IBC Vehicles’ breach of duty. The claimant did not have to show that the suicide itself was foreseeable. There was no break in the chain of causation, as the claimant’s decision to commit suicide was caused by the depression resulting from the breach of duty.

Contributory negligence

In Corr, the House of Lords unanimously held that suicide was “fault” within the meaning of section 1(1) of the Law Reform Miscellaneous Act 1945 (the Act) and therefore a finding of contributory negligence could be made. Although the law lords did not reduce the compensation payable in this particular instance, they agreed that it might sometimes be appropriate to cut down the damages payable in similar cases.

Following Corr, the Court of Appeal in Gray also considered the possibility of contributory negligence on the basis that the manslaughter was “fault” within the meaning of the Act. The loss of earnings was caused partly by the tort and partly by the claimant’s deliberate act of stabbing a stranger. Therefore, both parties were blameworthy. Rather than condoning the manslaughter, the court considered that apportionment would ensure the claimant only recovered losses for which the defendants were truly responsible. As the issues of foreseeability, causation and contributory negligence had not been pleaded or argued (only having been considered in the light of Corr), the Court of Appeal felt that the case ought to be remitted back to the High Court for consideration of these issues.


The Gray case did not involve a break in the chain of causation. On the evidence, the claimant would not have committed manslaughter without suffering from the PTSD caused by the defendant’s negligence.

Both sides agreed that if the claimant had committed a crime that was unrelated to the PTSD and unconnected to the defendant’s negligence, there would have been a complete defence to the claim for loss of earnings. However, as a matter of principle, if it is right to stop a claimant from recovering damages, the court should not decide that there was a break in the chain of causation. Instead, the court should say in clear terms that public policy requires that the claim should fail.

It is debatable whether the simple “but for” test of causation – tempered by apportionment of liability through contributory fault – is a good way of dealing with such extreme cases. This point was considered by the New South Wales Court of Appeal in State Rail Authority of NSW v Wiegold (1991). This case decided that, where a claimant has been convicted of a crime, they should bear both the direct and indirect consequences. Consequently, damages could not possibly be recovered for a period of incarceration. The Australian court rightly pointed out the potential harm to the justice system if the law of negligence said that an offender:

  • should not be held responsible for their actions; and
  • (just to add injury to insult) should also be compensated by the defendant.

This would lead to a conflict between the civil and criminal law and bring the law into disrepute.

There is one other factor that the Court of Appeal appears to have ignored. There is a wellestablished principle (hallowed by previous House of Lords’ decisions) that where the claimant experiences a change in circumstances since the cause of action arose – or the original act of negligence happened – the court will look at the actual position as known. It will not speculate about what might have happened if that change of circumstance had not taken place. In Gray, the Court of Appeal tackled the claim for continuing loss on the basis that the claimant would have been in employment both before and after commission of the offence and was therefore entitled to recover the whole of that loss. However, this approach looks little more than a way of ignoring the commission of a serious criminal offence when assessing damages.

Leave to appeal to the House of Lords has been granted to Thames Trains and their fellow defendants Network Rail Infrastructure Ltd (better known under their former name of Railtrack). Leave to cross-appeal has also been given to Mr Gray. It remains to be seen whether the House of Lords will choose to reassert the ex turpi principle, thereby limiting the loss that can be recovered in a personal injury action where the claimant has committed a serious criminal act for which he can fairly be held responsible.