Defences in tort: contributory negligence as a partial defence, consent (volenti non fit injuria) and illegality as complete defences, and necessity, including their requirements and effect.

What this dot point is asking

This dot point covers the defences a defendant can raise to a tort claim, especially in negligence. You need to distinguish a partial defence (contributory negligence, which reduces damages) from complete defences (consent/volenti and illegality, which defeat the claim), explain their requirements with cases, and apply them to a scenario, stating their effect. WJEC often asks you to advise a defendant on which defences are available.

The answer

Contributory negligence (partial defence)

It reduces rather than defeats the claim. In Froom v Butcher damages were reduced for a claimant who failed to wear a seatbelt; in Sayers v Harlow a claimant injured trying to climb out of a locked toilet had her damages reduced for the manner of her attempt. The reduction reflects a percentage of fault.

Consent: volenti non fit injuria (complete defence)

If established, volenti defeats the claim entirely. Its use by road users is restricted by statute, so it cannot defeat a passenger's claim against a negligent driver simply because the passenger accepted a lift.

Illegality and necessity

Illegality (ex turpi causa non oritur actio) is a complete defence: a claimant cannot found a claim on their own criminal conduct where that conduct is so closely connected to the harm that allowing recovery would be contrary to public policy. Necessity may justify otherwise tortious action taken reasonably to prevent a greater harm, though it is narrowly applied.

Examples in context

The seatbelt cases show contributory negligence in action. In Froom v Butcher the claimant was injured in a collision that was entirely the defendant's fault, yet because he had not worn a seatbelt his own carelessness had made the injuries worse, so his damages were reduced by a set percentage rather than extinguished. Volenti, by contrast, is all or nothing: in ICI v Shatwell two experienced shotfirers deliberately ignored safety regulations they knew well, so the employer escaped liability entirely because the men had freely accepted the precise risk. The contrast between the two defences is the heart of most exam questions: a defendant will usually prefer volenti or illegality, which defeat the claim, but will often have to settle for contributory negligence, which merely cuts the bill.

Try this

Q1. What is the effect of contributory negligence on a claim? [2 marks]

• Cue. It is a partial defence that reduces damages by a just and equitable amount (Law Reform (Contributory Negligence) Act 1945).

Q2. What must a defendant prove to establish volenti non fit injuria? [2 marks]

• Cue. That the claimant had full knowledge of the risk and voluntarily and freely agreed to run it (ICI v Shatwell).

Q3. Advise a defendant on the defences available to a claim in negligence. [20 marks]

• What the marker wants. Consent (volenti), contributory negligence, illegality and necessity identified and applied to the facts, with the effect of each (complete bar or reduction) and a conclusion.