In other words, if one is engaged in illegal activity, one cannot sue another for damages that arose out of that illegal activity.
In Scott v Brown (1892; quoted in a subsequent Supreme Court of Canada decision of 1894, Walsh v Trebilcock), Justice Lindley wrote:
"Ex turpi causâ non oritur actio. This old and well known legal maxim is founded on good sense, and expresses a clear and well recognized legal principle which is not confined to indictable offences. No court ought to enforce an illegal contract or allow itself to be made the instrument of enforcing obligations alleged to arise out of a contract or transaction which is illegal, if the illegality is duly brought to the notice of the court, and if the person invoking the aid of the court is himself implicated in the illegality. It matters not whether the defendant has pleaded the illegality or whether he has not. If the evidence adduced by the plaintiff proves the illegality the court ought not to assist him."
In Hardy, Justice Diplock wrote that the ex turpi rule means:
"... the courts will not enforce a right which would otherwise be enforceable if the right arises out of an act committed by the person asserting the right (or by someone who is regarded in law as his successor) which is regarded by the court as sufficiently anti-social to justify the court's refusing to enforce that right."
In Hall v Herbert, Justice Gibbs of the British Columbia Court of Appeal added:
"The principle underlying ex turpi causa is not limited to circumstances where the injuries are sustained during the course of a joint criminal enterprise.
"It is available wherever the conduct of the plaintiff giving rise to the claim is so tainted with criminality or culpable immorality that as a matter of public policy the court will not assist the plaintiff to recover. It is no longer the law in British Columbia that the defence is confined to cases of joint criminal enterprise or applies only in contract.
"The defence applied here, as fair-minded, right-thinking people would be outraged if the court lent its assistance to a drunk driver to recover damages from his drunk passenger."
An example is an injury suffered by a passenger in a stolen car, which that passenger knew to be stolen and was a free participant in the joyriding. If a vehicle crashes injuring the passenger, there may be no action in tort against the driver under the ex turpi causa non oritur actio principle.
Also sometimes referred to as simply ex turpi or ex turpi causa.
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