Using the objective test of the reasonable man, the Court determines whether a person has failed to act with reasonable care.
There are three stages to this inquiry. Firstly, the Court determines the attributes and qualities of the reasonable man. Secondly, the Court asks how much care the reasonable person would have taken. Thirdly, it asks whether the defendant took less care than the reasonable person would have done.
The cases below have been categorised based on these three questions.
1 – The attributes and qualities of the reasonable person
The Courts have generally been unwilling to consider the idiosyncrasies of a defendant. The following cases show the scope of this general rule, and the instances where the Court has taken into account the specific context of the defendant.
Nettleship v Weston 
Nettleship v Weston makes clear that the Court will not ordinarily take into account the idiosyncrasies of the defendant.
Mullin v Richards 
In Mullin v Richards, the Court of Appeal held that a defendant’s age is relevant for determining whether they have failed to take reasonable care.
Roe v Minister of Health 
The Court of Appeal confirmed that the reasonable person only has knowledge as is reasonable at the time of the act.
Roberts v Ramsbottom 
In Roberts v Ramsbottom, Neill J concluded that a defendant is only excused of failing to take reasonable care based on an illness where they have suffered from a total loss of consciousness. Borrowing from the criminal law, this must equate to automatism.
Mansfield v Weetabix 
The Court of Appeal overturned the approach in Roberts v Ramsbottom which required a ‘total loss of consciousness’, or actions which were ‘wholly beyond [the defendant’s] control’. Instead, the Court asked whether, objectively, the claimant failed to take reasonable care.
2 – How much care would the reasonable person have taken?
There is no single, set standard of care for the tort of negligence. Instead, the Court will consider a number of factors to determine what care the reasonable person would have taken. The following cases identify some of the most important factors which have help determine the appropriate standard of care.
Bolton v Stone 
In Bolton v Stone, the Court considered the likelihood of harm when deciding the expected standard of the reasonable person.
Haley v London Electricity Board 
In Haley v LEB, the Court again used the likelihood of harm to determine the expected standard of the reasonable person. Unlike in Bolton v Stone, the Court concluded that the defendant had not taken reasonable care.
Paris v Stepney BC 
In Paris v Stepney BC, an important factor the House of Lords considered was the gravity (or severity) of harm. This was balanced alongside the likelihood of harm.
Latimer v AEC Ltd 
In Latimer, the House of Lords took into account the cost of taking precautions when deciding what the reasonable person would have done. Where the cost of precaution is higher, the risk to others must be higher before the reasonable person would pay to take the costlier precaution.
Daborn v Bath Tramways 
The Court considered the utility of action when deciding what a reasonable person would have done in the defendant’s shoes.
Blake v Galloway 
In Blake v Galloway, the Court of Appeal established that informal games were to be treated analogous to formal sports games. Courts should ascertain the rules of the game, and then determine the standard of care expected of participants accordingly.
3 – Proving the defendant failed to take reasonable care
The claimant must show that, on the balance of probability, the defendant failed to meet the standard of the reasonable person. This is a straightforward exercise in most cases.
Cases of professional negligence, in particular medical negligence, have caused more controversy. In these cases, the Courts may take into account the opinion of a reasonable body of the profession when deciding if the defendant took reasonable care. It is these cases that this section focuses on.
Bolam v Friern Hospital Management Committee 
In Bolam v Friern Hospital Management Committee, the Court stated and applied what has become the ‘Bolam principle’. The Bolam principle is that: a professional who follows conduct advocated by a reasonable proportion of their respective profession will not have failed to take reasonable care.
Bolitho v City and Hackney Health Authority 
In Bolitho, the House of Lords followed and applied the Bolam principle. Whilst a layman may conclude that the doctors acted negligently, a Court is unable to ignore evidence from a professional that is capable of standing up to rational analysis.
Montgomery v Lanarkshire Health Board 
In Montgomery v Lanarkshire Health Board, the Supreme Court concluded that the decision by a doctor on whether to disclose a risk to a patient is not subject to the Bolam principle. This is because the decision is a ‘value judgement’, rather than informed by medical learnings and experience.