In Pitts v Hunt [1991] 1 QB 24, Dillon LJ stated:

It is clear for a start that the fact that a plaintiff was engaged in illegal activity which brought about his injury does not automatically bring it about that his claim for damages for personal injury as a result of the negligence of the defendant must be dismissed.

The facts of the case were that the plaintiff and defendant had been on a joint drinking spree and were both heavily intoxicated. The plaintiff rode pillion on the defendant's motorbike encouraging the defendant to drive recklessly. The Court of Appeal stated that the joint illegality made it impossible to apply a standard of care and, therefore, the action should fail.