Tort Law: Negligence, Breach and Causation

Once a duty of care is established, a claimant in negligence must still prove breach of that duty and that the breach caused actionable damage that is not too remote. This guide covers the standard of care, the factors that decide whether the standard was breached, and the law of causation.

1. The Standard of Care

The defendant is judged against the objective standard of the reasonable person doing the activity in question.

The standard does not bend for inexperience. A learner driver is held to the standard of a competent driver (Nettleship v Weston), and a child is judged against a reasonable child of the same age (Mullin v Richards).

Professionals

A professional is judged by the standard of a reasonably competent member of that profession, and is not negligent if acting in accordance with a practice accepted as proper by a responsible body of professional opinion.

2. The Risk Factors

Whether the reasonable person would have taken more precautions is decided by weighing several factors.

Likelihood of harm

The lower the probability of harm, the less is required. In Bolton v Stone a cricket ball had cleared the ground only a handful of times in decades, so the risk did not require further precautions.

Seriousness of harm

The graver the potential injury, the more is required. In Paris v Stepney BC an employer should have provided goggles to a worker known to have sight in only one eye, because the consequences of injury were far worse for him.

Cost of precautions and social utility

The court weighs the cost and practicability of precautions (Latimer v AEC) and the social utility of the defendant's activity, so emergency services taking risks to save life are judged accordingly (Watt v Hertfordshire CC).

3. Factual Causation

The claimant must show the breach caused the damage. The basic test is the "but for" test: but for the breach, would the harm have occurred?

Where science cannot pinpoint a single cause, the courts may ask whether the breach made a material contribution to the harm (Bonnington Castings v Wardlaw) or materially increased the risk (McGhee v National Coal Board).

4. Legal Causation and Remoteness

Even where factual causation is made out, a new intervening act (novus actus interveniens) by a third party, the claimant, or nature may break the chain. Beyond that, the damage must not be too remote.

The precise way the harm occurs, and its extent, need not be foreseeable, only the kind of harm (Hughes v Lord Advocate). And under the thin skull rule, the defendant takes the victim as they find them, so unusual susceptibility does not reduce liability (Smith v Leech Brain).

5. Worked Example

Breach: a reasonably competent garage would not leave the brakes faulty, so the standard is breached. Factual causation: but for the faulty brakes, would the crash have happened? Arguably yes in part. Intervening act:the driver's decision to speed despite knowing of the fault may amount to a novus actus or, more realistically, contributory negligence reducing damages.

Examiner Insights

Conclusion

Breach and causation are where most negligence problems are won or lost. Set the standard, weigh the risk factors, prove the breach was a but-for cause, deal with any intervening acts, and confirm the harm was a foreseeable kind. That sequence keeps a messy fact pattern under control.