What is the difference between complete defence and and partial defence to a tort action under English law?

A complete defence is a defence that completely negates the plaintiff’s claim, and therefore the defendant will be found not liable for the tort. A partial defence is a defence that does not completely negate the plaintiff’s claim, but instead reduces the amount of damages the defendant is liable for. Partial defences include contributory negligence, volenti non fit injuria (voluntary assumption of risk) and contributory fault.