In tort, there can be no liability in negligence unless the claimant establishes both that he or she was owed a duty of care by the defendant, and that there has been a breach of that duty. The defendant is in breach of duty towards the claimant if his conduct has fallen short of the standard that he was expected to meet in the circumstances.
General standard of care
In order not to breach a duty of care, a defendant must generally meet the standard of a 'reasonable man' as Baron Alderson stated in Blyth v Birmingham Waterworks (1856) 11 Exch 781.
A reasonable person can be defined as 'the man on the Clapham omnibus' as Greer LJ explains in Hall v. Brooklands Auto-Racing Club (1933) 1 KB 205. Lord Steyn describes the term as 'commuters on the London Underground' ( McFarlane v. Tayside Health Board (1999) 3 WLR).
This is an objective standard, based on an average person. It does not require perfection, but takes into account that an average person does not foresee every risk. The average person is not assumed to be flawless, but ordinarily careful and prudent.
The standard of "the man on the Clapham omnibus" is not applied in all cases, since this might lead to unfairness. There are defendants for whom this standard is much too low and would exonerate an obvious wrongdoing. In other cases, the standard may be seen as too demanding of the defendant in the circumstances. The most common examples are the cases of specialist defendants, inexperienced defendants and child defendants.
Skilled defendants (specialists)
The test of an ordinary average person would not be appropriate for defendants that profess or hold themselves out as professing a certain skill. The "man on the Clapham omnibus" does not have that skill and the conduct expected from a skilled professional is not the same as could be expected of an ordinary man in the same circumstances. The general standard applied to professionals is therefore that of a "reasonable professional", e.g. car mechanic, doctor etc.
Novices in a certain area of skill must show the same standard of care as a reasonable person with that particular skill. No allowance is given for the defendant's lack of experience.
- Nettleship v. Weston (1971) 3 All ER 581 requires a novice driver to show the same standard of care as a reasonably competent driver.
- Wilsher v. Essex Area Health Authority (1986) 3 All ER 801 expects a junior doctor to perform compliant to the standard of a competent doctor.
- Wells v. Cooper (1958) 2 All ER 527 states that someone who does DIY jobs repairing their own house is expected to show the same standard of care as a reasonable professional of the particular trade involved.
It is important to note that the claimant's knowledge of the defendant's lack of experience in the skill he is exercising does not result in the standard being lowered. In Nettleship v. Weston, the driving teacher was injured due to a mistake of his student. The student argued that the driver was aware of her lack of experience, but the court refused to accommodate this fact in their decision on the standard of care expected from her. At the same time, the teacher's award of damages was reduced due to his contributory negligence.
While no allowance is made for novices, the courts are prepared to lower the standard for children on the account of their age. A child defendant is expected to meet the standard of a reasonable child of the same age.
- Gough v. Thorne (1966) 3 All ER 398: a 13½ year old girl was not contributorily negligent when she crossed the road without looking after being beckoned by a lorry driver and was hit by a car driving at excessive speed.
- Mullin v. Richards  1 All ER 920: a fifteen year old girl was not negligent when she was play fighting with a friend and a ruler she was fencing with shattered, a splinter flying into the other girl's eye.
Conduct expected of a reasonable person
In the usual case, having established that there is a duty of care, the claimant must prove that the defendant failed to do what the reasonable person ("reasonable professional", "reasonable child") would have done in the same situation. If the defendant fails to come up to the standard, this will be a breach of the duty of care. This is judged by reference to the following factors:
- What did the defendant know? According to Denning LJ. in Roe v Minister of Health (1954) 2 AER 131, the defendant will only be liable if the reasonable person would have foreseen the loss or damage in the circumstances prevailing at the time of the alleged breach of duty.
- What was the degree of risk? The greater the risk that serious harm can be inflicted, the greater the precautions that the defendant will be required to take. In Bolton v Stone A.C. 850,  1 All E.R. 1078, a cricket club was not negligent when a ball was hit out of the ground and injured the plaintiff, because the likelihood of this occurring was so small that the defendant could not be expected to have taken precautions. In Miller v. Jackson ( QB 966,  3 WLR 20,  3 All ER 338 however, the ball was hit out of the ground several times every season. In these circumstances, the club was expected to take precautions.
- How practical were these precautions? In Wilson v Governor of Sacred Heart Roman Catholic Primary School (1997) EWCA Civ 2644 it was held that a primary school was not negligent in not employing someone to supervise the playground after the close of school hours and until all the children had left. In Haley v London Electricity Board  3 All ER 185, a blind man fell into a hole in the ground which was indicated by a visual sign. He became deaf as a result. It was held that it was foreseeable that a blind man would be walking on the street and the risk of him injuring himself justified the precautions of putting up a barrier. The test is a balance of reasonableness of precautions against the likelihood of injury being sustained.
- What is the social importance of the defendant's activity? If the defendant's actions serve a socially useful purpose then he or she may have been justified in taking greater risks. Thus, in Watt v Hertfordshire CC (1954) 2 AER 368, the fire brigade was not negligent in getting the wrong vehicle to the scene of an accident because valuable time would have been lost in getting the best vehicle there to help. Since 26 July 2006, this consideration has had a statutory basis under section 1 of the Compensation Act 2006.
- Common practice. A defendant complying with a common practice in his area of activity will usually be considered to have met the standard of a reasonable man, unless the court judges the practice itself to be negligent. In Paris v Stepney Borough Council (1951) 1 AER 42 although there was a practice of not providing employees with safety goggles, the Council owed a special duty to protect the claimant because he had already lost the sight of one eye.
The conduct expected from a participant in a sports event towards his competitors or spectators differs from the conduct of a reasonable person outside such events. It has been held that in the "heat and flurry" of a competition, a participant will only be in breach of duty towards other participants and spectators if he shows "reckless disregard for their safety". At the same time, in another case,
the standard of care expected from one player towards another is the usual standard of taking "all reasonable care in the circumstances in which they were placed", although in that case the defendant was also found to be acting recklessly. It is not clear at present if and how the two approaches can be reconciled.
Burden of proof
Whether or not the defendant in a given case has conducted himself below the standard of "a reasonable person" is a question of fact and it is for the claimant to prove this fact. However, in certain situations it is unlikely that a certain even could take place without the defendant's negligence, for example if a surgeon left a scalpel in the patient's body. In such cases, it is said that "the thing speaks for itself" (res ipsa loquitur
), and it is for the defendant to show that the fact causing the damage was not attributable to his negligence.
- Wenham, David. (1998). "Negligent Children". 4 WebJCLI