The maxim ‘ex turpi causa non oritur actio’ means 'no action may be based on an illegal cause' and appears to rest on the idea that the courts will not help/compensate a claimant where it would be 'an affront to the public conscience' to do so, and might encourage the claimant, or others, in illegal activities. Basically, it operates to deny compensation to a wrongdoer. The principle is based on public policy considerations and there is uncertainty in both its application and justification. Again, it is a complete defence