Breach of Duty
The Basic Test
Reasonable Person
A person is negligent if they fail to act as a reasonable person would have done: Blyth v Birmingham Waterworks Company (1856) 11 Ex Ch 781.
Relevant factors include:

How foreseeable the harm was: Roe v Minister of Health [1954] 2 WLR 915.

The seriousness of the harm: The Wagon Mound (No 2) [1967] 1 AC 617.

Any special vulnerabilities the defendant knows the claimant has (Paris v Stepney [1951] AC 367) or which a reasonable person would foresee: Haley v London Electricity Board [1965] AC 778.

The cost and effort of precautions: Latimer v AEC [1953] AC 643.

The social utility of the defendant’s activity: Humphrey v Aegis Defence Services [2016] EWCA Civ 11.

The ordinary risks inherent to a game and the rules of sport: Wattleworth v Goodwood Road Racing Co [2004] EWHC 140 (QB).
Raising the Standard
Professionals and Special Skills
For professionals and people who indicate they have special skills, the standard of care is of a reasonable professional in the same field with the same qualifications. This standard is not lowered if the defendant is a learner, trainee or is inexperienced: Wilsher v Essex AHA (1987) 1 QB 730. The standard imposed on professionals is subject to the Bolam test.
The Bolam Test: if the defendant acted in a manner which would would be accepted as proper practice by a responsible body of professionals skilled in the same art, he is not negligent: Bolam v Friern [1957] 1 WLR 583.
Caveat to the Bolam Test: However, the responsible body of professionals must have logical and defensible reasons to accept the practice as proper. Otherwise, the practice is negligent: Bolitho v City & Hackney HA [1997] 3 WLR 1151.
‘Duty to Inform’ Cases
The Bolam test does not apply where the professional is under a duty to warn the claimant on the risks of undertaking a particular action: Montgomery v Lanarkshire Health Board [2015] UKSC 11. Instead, the defendant must disclose all ‘material’ risks. This is any risk which a reasonable claimant would think significant, or which the professional believes the claimant think significant.
Lowering the Standard
No Lower Standard for Trainees
The standard of care in negligence is not lowered if the defendant is a learner, trainee or is inexperienced: Nettleship v Weston [1971] 3 WLR 370.
Cases Where the Standard is Lower

Children are only required to act as a reasonable child of the same age would: Mullin v Richards [1998] 1 WLR 1304.

People who are unaware they have a physical illness need only act like a reasonable ill person who is also unaware: Mansfield v Weetabix [1997] EWCA Civ 1352. This is not the case if the claimant has reason to believe they are ill: Roberts v Ramsbottom [1980] 1 WLR 823.

People engaging in consensual ‘horseplay’ are only negligent if their conduct is reckless or highly careless: Blake v Galloway [2004] 3 All ER 315.
Res Ipsa Loquitur
What is Res Ipsa Loquitur?
Ordinarily, the claimant must provide specific proof of the actions and omissions they allege to be the breach. However, the doctrine of res ipsa loquitur allows the claimant to succeed even when they cannot prove what exactly caused the accident. The doctrine applies whenever the claimant can show that:
- The defendant had the power to manage or control the situation in which the accident occurred; andÂ
- The accident does not ordinarily happen, assuming proper care is used in managing or controlling the situation: Scott v London and St Katharine Docks Co (1865) 3 H&C 596.
The Effect of Res Ipsa Loquitur
The doctrine does not strictly shift the burden of proof onto the defendant: Ng Chun Pui v Lee Chuen Tat [1988] RTR 298. Rather, it provides prima facie evidence which can discharge the claimant’s burden of proving breach. The defendant can provide a contrary explanation. If they so, the judge must re-evaluate whether it is still reasonable to assume the accident must have resulted from negligence.