P challenged D to a fight and hit D lightly, before P hit P severely, causing P serious injury, for which P sued. CA held that since P had struck a blow out of all proportion, the defences of “ex turpi causa” and “volenti” do not apply.
Lord Denning MR: “Even if the fight started by being unlawful, I think that one of them can sue the other for damages for a subsequent injury if it was inflicted by a weapon or savage blow out of all proportion to the occasion. I agree that in an ordinary fight with fists there is no cause of action to either of them for any injury suffered. The reason is that each of the participants in a fight voluntarily takes upon himself the risk of incidental injuries to himself. Volenti non fit injuria. But he does not take on himself the risk of a savage blow out of all proportion to the occasion.”