Breach of duty

Breach of duty is the second central inquiry in negligence. After Weeks 1 to 4, you should be comfortable asking whether the defendant owed the claimant a duty of care, including in difficult cases involving psychiatric injury, pure economic loss, omissions and public authorities. Week 5 asks a different question: assuming a duty exists, did the defendant fall below the standard required by law? The inquiry is not whether the defendant was morally defective, unlucky, or imperfect. It is whether the defendant failed to take reasonable care in the circumstances. The governing idea is deceptively simple. In Blyth v Birmingham Waterworks Co, Alderson B defined negligence by reference to what a reasonable person would do or not do. That formulation remains the core of breach. Yet almost all the intellectual difficulty lies in specifying what the reasonable person must do when risks are small but grave, precautions are costly but feasible, the defendant is a child or professional, the activity is socially valuable, or standards evolve with knowledge and technology. Breach is therefore the meeting point of principle, policy and fact. It is more fact-sensitive than duty, but it is not mere impressionism. Courts use recognised factors: the probability of harm, the seriousness of possible injury, the burden of precautions, the utility of the defendant's conduct, common practice, professional judgement, and the state of knowledge at the time. These factors are not a mathematical formula. English law does not formally adopt the American Learned Hand calculus. But the same structured reasoning is visible in cases such as Bolton v Stone, Paris v Stepney Borough Council, Latimer v AEC Ltd and Watt v Hertfordshire CC. For Durham first-year purposes, breach is also a bridge topic. It tests legal method: how a general standard is developed through precedent, how appellate courts treat factual evaluations, and how statutory provisions such as the Compensation Act 2006 and the Social Action, Responsibility and Heroism Act 2015 interact with the common law. It also anticipates later questions of causation, remoteness, defences and damages. A claimant may establish duty and breach but fail on causation; conversely, a defendant may have caused harm without having acted unreasonably. Keep those inquiries analytically separate. The strongest exam answers do not recite a checklist mechanically. They identify the relevant standard, justify the factors that matter on the facts, and explain why the balance of risk and precaution makes the defendant's conduct reasonable or unreasonable.

The modern law of breach grew from nineteenth-century attempts to give negligence an objective and administrable shape. Earlier liability often depended on forms of action, relationships, or particular duties. By the mid-nineteenth century, industrialisation made accidental injury a recurring legal problem: railways, factories, utilities and urban infrastructure created risks not easily captured by older categories. The law responded by articulating a general standard of reasonable care. Blyth v Birmingham Waterworks Co is conventionally treated as the classical starting point. A water main burst after an unusually severe frost. The defendant had complied with ordinary practice and the event was extraordinary. Alderson B's formulation detached negligence from the defendant's subjective state of mind and made it turn on the conduct expected of a reasonable person under the circumstances. That objective standard was essential to negligence becoming a general tort. It allowed courts to ask not whether this defendant did his best, but whether the defendant did what the law required. During the twentieth century, the courts refined the standard through risk analysis. Bolton v Stone concerned a very small risk of cricket balls being hit out of a ground. The House of Lords held that not every foreseeable risk requires precautions; reasonableness requires attention to the likelihood of injury. Paris v Stepney then showed that the seriousness of potential harm matters: a worker with only one good eye faced a qualitatively more serious risk from flying metal, so goggles might be required even if they were not generally provided to others. Latimer v AEC Ltd added the burden of precautions: after a factory flood, the employer spread sawdust and warned employees; shutting the factory altogether was not required. Watt v Hertfordshire CC recognised the social utility of emergency services, holding that greater risks may be reasonable where life-saving work is being undertaken. A separate strand concerned expertise. In Bolam v Friern Hospital Management Committee, McNair J formulated the professional negligence test: a professional is not negligent if acting in accordance with a practice accepted as proper by a responsible body of professional opinion. That test gave substantial deference to professional judgement, especially in medicine. Bolitho v City and Hackney Health Authority later qualified it: the professional opinion must withstand logical analysis. This development is crucial because breach is not always judged by a layperson's common sense. Sometimes the relevant standard is that of the reasonable skilled professional, the reasonable driver, the reasonable occupier, the reasonable employer, or the reasonable child of similar age. Recent history has involved legislative interventions responding to perceived compensation culture. Section 1 of the Compensation Act 2006 permits courts to consider whether imposing precautions would deter desirable activities. The Social Action, Responsibility and Heroism Act 2015 requires courts to have regard to social action, responsible conduct and emergency intervention. These provisions have not transformed negligence doctrine, but they signal a political concern that breach should not be assessed with unrealistic hindsight. Historically, therefore, breach has moved from a single objective phrase to a structured, contextual evaluation of risk, precaution, activity and role.

1. The standard is objective. The defendant is measured against the conduct of a reasonable person in the defendant's position, not against the defendant's personal capacities, anxieties, inexperience or good intentions. This is the significance of Blyth and Nettleship v Weston. In Nettleship, a learner driver was judged by the standard of the reasonably competent driver, not by the lower standard of an inexperienced learner. The rule protects claimants and promotes public standards of conduct. If road users could invoke inexperience, the standard of safety would become unpredictable. The objective standard also reflects negligence's public function: it sets a common minimum of behaviour for activities that expose others to risk. 2. The standard is objective but contextual. Objectivity does not mean abstraction from facts. The reasonable person is placed in the circumstances of the defendant. A surgeon is not judged as an ordinary householder; a schoolchild is not normally judged by adult standards; an emergency responder is not judged as though acting in calm conditions. The law therefore distinguishes between subjective excuses, which generally do not lower the standard, and relevant circumstances, which shape what reasonable care requires. The difficult question is whether a fact belongs to the person or the situation. Inexperience in driving is personal and ignored. Childhood is treated differently: in Mullin v Richards, a 15-year-old girl playing with plastic rulers was judged by the standard of an ordinarily prudent and reasonable 15-year-old. 3. Foreseeability of harm is necessary but not sufficient. A defendant is not negligent merely because harm was foreseeable. Most ordinary activities carry some foreseeable risk. The law asks whether the risk was such that reasonable precautions were required. Bolton v Stone is the leading illustration. The cricket club could foresee that a ball might rarely leave the ground, but the likelihood was extremely low and previous experience supported the conclusion that no further precautions were required. Conversely, if a risk is common or obvious, failure to guard against it may readily be a breach. The relevant foreseeability is assessed at the time of the defendant's conduct, not with hindsight after injury occurs. 4. The seriousness of possible harm matters. Paris v Stepney shows that reasonable care may require greater precautions where the potential consequences are especially grave. The claimant's one-eyed condition meant that injury to his remaining eye would be catastrophic. The employer knew this.

The leading cases form a coherent structure if read as responses to particular breach factors. Blyth supplies the general objective standard. It is the anchor case and should normally appear at the start of a breach analysis. The waterworks company was not liable because the frost was extraordinary and reasonable precautions, judged by contemporary standards, did not require guarding against such an unusual event. Bolton v Stone develops the probability dimension. Cricket balls had occasionally been hit out of the ground, but the risk of injury was very small. The House of Lords refused to treat mere foreseeability as breach. The case is frequently misused. It does not say that low-probability risks can be ignored; it says that probability must be weighed with gravity, precautions and context. Paris v Stepney represents gravity of harm. The employer knew that the claimant had only one useful eye. The risk of eye injury may have been similar to other workers, but the consequences for this claimant were much more serious. Reasonable care therefore required precautions that might not have been required for all employees. Latimer v AEC Ltd concerns the burden of precautions. After flooding made the factory floor slippery, the employer spread sawdust and warned workers. The only further precaution suggested was closing the factory. The House of Lords held that this was not required. Latimer is useful for resisting hindsight: the fact that an accident occurred does not prove that more had to be done. Watt v Hertfordshire CC supplies social utility. The fire brigade took risks in transporting equipment because life-saving urgency demanded speed. The case should be contrasted with ordinary commercial convenience. Social utility is strongest where the activity protects life or safety, weaker where the defendant merely seeks profit or efficiency. Nettleship v Weston is essential on the objective standard for adult activities requiring competence. A learner driver owes the standard of the reasonably competent driver. This may seem harsh, but compulsory insurance and the need for road safety explain the rule. Mullin v Richards qualifies objectivity for children. The standard is that of a reasonable child of the defendant's age, not a reasonable adult. The law recognises developmental capacity without making each child's actual immaturity decisive. Bolam and Bolitho govern professional breach. Bolam gives weight to responsible professional practice. Bolitho prevents professional self-regulation from being conclusive where the opinion lacks a logical basis. In medical negligence, the distinction between diagnosis/treatment and advice about risks must also be remembered. Montgomery v Lanarkshire Health Board altered the approach to disclosure of medical risks, making patient autonomy central; it is often taught under breach or consent, but its conceptual significance is wider. The cases collectively show that breach is not a single mechanical test. It is an objective standard refined by recurring categories of reasonableness.

See practice questions section below.

See further reading section below.