Breach of duty

Breach of duty requires the defendant to have fallen below the standard of the reasonable person in their position. The test, from Blyth v Birmingham Waterworks Co (1856), asks whether the defendant omitted to do something a reasonable person would do, or did something a prudent reasonable person would not do. This is an objective standard calibrated by context: courts weigh the likelihood and gravity of harm against the burden of precautions (the risk calculus). The inquiry is not whether the defendant tried their best or acted honestly, but whether their conduct met the law's required standard. For professionals, the Bolam test applies: they must act in accordance with a practice accepted by a responsible body of professional opinion, though Bolitho requires such opinion to be logically defensible. The standard serves to compensate victims and set public behavioural expectations, not merely to punish moral wrongdoing.

Blyth v Birmingham Waterworks Co (1856) 11 Ex 781: Established the objective reasonable person standard—negligence is failing to do what a reasonable person would do in the circumstances. Remains the foundational definition.

Bolton v Stone [1951] AC 850: Very small risks need not be guarded against—cricket ball hit out perhaps six times in thirty years created no duty to take precautions. Establishes that probability of harm is central to the breach calculus.

Paris v Stepney Borough Council [1951] AC 367: One-eyed workman required greater protection because potential harm (total blindness) was more serious. Shows the standard adjusts for known vulnerabilities affecting gravity of harm.

Bolam v Friern Hospital Management Committee [1957] 1 WLR 582: Professional negligence judged by whether defendant acted per responsible professional opinion, even if others disagree. Creates deference to professional judgment on technical matters.

Nettleship v Weston [1971] 2 QB 691: Learner drivers held to standard of competent drivers—no reduction for inexperience. Confirms strict objectivity for public safety and insurance reasons.

Montgomery v Lanarkshire Health Board [2015] UKSC 11: For informed consent, test is patient-centred (material risk disclosure) not profession-centred. Limits Bolam to technical medical judgment, not information disclosure.

Courts apply a multi-factorial risk calculus weighing: (1) Probability of harm—more likely injuries require greater precautions; (2) Gravity of potential harm—serious risks demand more care than trivial ones; (3) Burden of precautions—cost and practicability matter; disproportionate measures not required; (4) Social utility—emergency services get latitude for valuable activities; (5) Common practice—evidence of reasonableness but not conclusive.

The defendant is judged as a reasonable person in their position, with their knowledge but not personal incapacities. Learners and mentally ill defendants get no concession; children judged as reasonable children unless performing adult activities. Professionals judged by Bolam standard (responsible professional opinion) except for consent (Montgomery—patient perspective on material risks).

Res ipsa loquitur permits inference of breach where accidents don't normally occur without negligence, defendant controlled the instrument, and cause unknown to claimant—but it's evidential inference, not burden reversal.

Conflating duty and breach: Where duty is straightforward, focus on breach—apply the risk calculus explicitly citing Bolton, Paris, Latimer.

Misapplying Bolam/Montgomery: Bolam governs diagnosis/treatment; Montgomery governs informed consent. Don't apply wrong test.

Forgetting multi-factorial analysis: Don't just assert carelessness—systematically weigh probability, gravity, burden, utility.

Overstating res ipsa: It's circumstantial inference, not burden reversal. Defendant can rebut with evidence of reasonable care.

Ignoring objective standard's rationale: Essay questions on Nettleship/mental illness require policy discussion—victim compensation, insurance, equal respect.

Conflating breach with causation: Breach means substandard conduct; whether it caused loss is separate. Keep elements distinct.