Negligence: Breach of Duty and the Reasonable Person Standard
Breach asks whether the defendant's conduct fell below the standard of the hypothetical reasonable person - not whether harm occurred, and not whether the defendant meant well.
The objective standard
Blyth v Birmingham Waterworks defines negligence as doing what a reasonable person would not do, or omitting what he would do. Glasgow Corporation v Muir confirms the standard is independent of the defendant's temperament. The standard is therefore objective, with narrow exceptions:
- Learners: judged as a competent driver or professional; their inexperience is no defence (Nettleship v Weston).
- Children: judged against a reasonable child of the same age (Mullin v Richards).
- Skilled defendants: the ordinary skilled member of the profession (Bolam), and with patients the duty now extends to material risks.
The risk calculus
Reasonableness depends on balancing factors:
- Probability of harm: Bolton v Stone (cricket ball over a high fence, very rare) negates breach.
- Seriousness of likely injury: Paris v Stepney - a one-eyed worker should have had goggles.
- Cost and practicability of precautions: Latimer v AEC - a gravel floor after flooding was a reasonable, not perfect, response.
- Social utility: Watt v Hertfordshire - urgency of saving life excuses some risk.
- State of knowledge: Roe v Minister of Health - no breach for risks unknown at the time.
Proving breach and res ipsa loquitur
Breach is for the claimant to prove on the balance of probabilities. Res ipsa loquitur (Scott v London and St Katherine Docks) lets the inference arise where the thing causing harm was under the defendant's control and the accident would not ordinarily happen without negligence. Its effect is evidential: the defendant must offer an explanation, but it does not reverse the burden into strict liability.
Worked example
A hospital patient develops an infection from a contaminated batch of dressings; the batch was prepared in the hospital. The injury would not ordinarily occur without negligence and the whole process was controlled by the hospital. Res ipsa loquitur permits the inference of breach; the hospital must show a reasonable system or an explanation, not merely that it was careful in general.
Traps that cost marks
Using hindsight to judge a defendant who acted on contemporary knowledge; asserting res ipsa loquitur as a rule of strict liability; treating expert practice as conclusive, rather than as evidence; and ignoring the cheapness of a precaution when the injury risked is severe.