Civil liability for negligence is discussed generally on the Personal injury page, the present page focuses mainly on the OH practitioner’s personal liability for this towards workers, job applicants and other individuals.

  • The level of duty required is to take reasonable care, the care of the average OH. The duty may sometimes lead to Tensions with the employer.
  • For civil (as opposed to criminal) liability there must normally be some damage. Courts tend to be more willing to find liability for physical (including psychiatric) damage than for economic loss.
  • As regards to whom the OH practitioner is liable, there are tests of proximity and whether it is just and reasonable to impose a duty of care. There are sections below on Existing employees, Job applicants, and third parties such as employees of contractors or members of the public.
  • In the case of liability to job applicants, the Kapfunde case held there to be no liability for economic loss (failing to get the job) on the part of an OH doctor reviewing pre-employment questionnaires, at least where he did not see the individual.
  • Where there is a public interest in disclosing confidential information, the question can arise whether there is ever a legal duty to breach confidence.
  • As well as civil liability for negligence discussed on this page, there are other possible liabilities of the OH practitioner, including under the Equality Act – see separate page OH practitioner liability under EqA.
  • Where the OH practitioner is liable, eg for harm which results from negligently not warning a person of a medical risk, the employer will sometimes be vicariously liable as well. A 2020 case limits the extent to which this can apply if the OH practitioner is not directly employed. Below Is an employer vicariously liable for negligence of an OH professional?

Level of duty

Doctors and nurses owe a duty of care to those within the foreseeable area of risk. This is a duty to take reasonable care, the care of the average OH professional. The courts determine what an average member of the profession should have done by relying on expert witnesses. In most cases today only one expert will be allowed to give evidence if the case goes to court; the court will direct that a joint expert be appointed.

This test, known as the Bolam test after the case in which it was originally established, was refined by the House of Lords in Bolitho v City and Hackney HA (1998). The standard of care is that of a ‘responsible, reasonable and respectable practitioner’.

Stokes v Guest Keen Nettlefold [1968] I WLR 1776
A toolsetter died of scrotal cancer. In the course of his employment the front of his overalls was regularly soaked with carcinogenic oil. This was before COSHH, but in 1960 the Factory Inspectorate had advised employers to warn and monitor those who worked with the oil. The widow sued the company, and the court upheld her claim. The OH physician (who was an employee of the company) was negligent and the company was vicariously liable. He knew of the risk, but failed to warn or undertake health surveillance. He had talked about risk in a meeting (which Stokes did not attend), but mention of scrotal cancer had been omitted from minutes which were circulated generally, because they were also read by women.
Note: the OH physician would presumably have been personally liable as well as the employer, if the widow had chosen to sue him directly.

Brown v Rolls-Royce [1960] 1 All ER 577
The OH physician advised the employer that it was not necessary to provide barrier cream for a particular process, because its efficacy had not been demonstrated. There was a difference of opinion in the profession. Brown contracted dermatitis. It was held that there was no negligence because it had not been proved that barrier cream was an effective precaution.

Where the OH practitioner engages in clinical practice – for example in deciding whether to prescribe post-exposure prophylaxis to a health care worker following a potential exposure to a bloodborne virus, or whether to offer influenza or travel vaccination – the approach to informed consent in Montgomery v Lanarkshire Health Board will apply: see Consent>Informed consent. Accordingly the patient should be given the information a reasonable patient would be likely to consider significant, or which the practitioner is or should reasonably be aware the particular patient would be likely to consider significant.

Tension with employer?

The OH practitioner might advise an employer that certain steps are required but the employer fails to take action. The employer could then itself be liable for negligence if damage results. However, there is also potential liability of an OH practitioner for failure to warn workers, and there may be ethical duties to warn. This can put practitioners in a quandary if an employer does not want him to ‘rock the boat’. Whistleblowing legislation may help if the OH practitioner is an employee or ‘worker’ – but not otherwise where the practitioner is concerned about losing their contract. (See also below Liability to third parties, such as employees of contractors or members of the public?)


An important difference between civil and criminal law is that in civil law the ‘perpetrator’ is only liable if there has been damage. Someone can face criminal prosecution under the HSW Act for an unsafe machine, but under civil law the claimant must normally show damage.

It may be physical damage to the claimant’s person or to property. As regards the claimant’s person, that can include psychiatric damage. Alternatively it may be economic damage, eg the claimant getting the sack because OH was negligent. The courts are more willing to compensate for damage flowing from physical harm than for ‘pure economic loss’, unless there is a close relationship between the parties, usually a contract. This leads on to the question:

To whom is the OH practitioner liable?

The leading case on whether someone owes a duty of care in negligence to a particular claimant is:

Caparo v Dickman, House of Lords, 1990
Caparo Industries plc had made a takeover bid for Fidelity plc on the basis of the accounts sent to them as shareholders. On completion of the takeover it was found the financial position was worse than stated. Caparo’s claim against the auditors failed. In the absence of a contract, the auditors were held not to have a duty of care to Caparo in the circumstances. For a duty of care to arise in a novel situation, (1) the damage or loss must be foreseeable, (2) the relationship between wrongdoer and victim must be sufficiently close (proximity), and (3) it must be just and reasonable to impose a duty of care.

The three-part test in Caparo is not the only one applied by the courts – another for example is whether the defendant has ‘assumed’ liability. However, Caparo is the test which figures most commonly.

Liability to existing employees

An OH practitioner may be personally liable for failing to protect existing employees against risks to physical or mental health while at work, in the part of the workplace over which he has jurisdiction, as in the Stokes and Brown cases above. Bear in mind though that this is just a duty to take the care an average professional would in the circumstances: see above Level of duty.

The OH practitioner’s duty may well also extend to other people on the site, such as contractors, or perhaps for example patients if the workplace is a hospital. See below Liability to third parties, such as employees of contractors or members of the public?

The practitioner also has a particular duty of care towards a worker who approaches him for advice or assistance, eg. as regards not making a negligent diagnosis.

What about reports to the employer on the employee’s health – for example if the OH practitioner negligently reports that the employee is not fit for work? In Spring v Guardian Assurance (1993) the House of Lords held that an employer could be liable for negligently giving an incorrect reference about an employee to another employer. This implies that the OH practitioner may be liable to the individual for the content of reports to the employer. However, as discussed below, in Kapfunde this was held not to apply to an OH practitioner reviewing pre-employment questionnaires, at least where the practitioner had not seen the job applicant.

What if protecting other workers would involve disclosing medical information without the patient’s consent? See below Is there ever a legal duty to breach confidence.

The OH practitioner obviously also has a duty to the employer. However, quite apart from the practitioner’s duties towards the employer in tort, there will nearly always be a contract with the employer giving rise to contractual obligations.

Liability to job applicants

The Kapfunde case held that an OH practitioner had no duty to a job applicant for economic loss, ie. for the applicant’s failure to get the job, at least where the practitioner had not seen the job applicant. However, an OH practitioner may owe a duty to a job applicant in respect of physical harm.

Job applicants: Economic loss

As regards not being liable for economic loss, the earlier case of Baker v Kaye [1997] IRLR 219 considered that a doctor could be liable for damages if he examined a job applicant for an employer and negligently pronounced him unfit for work. (The doctor was held not negligent though, and so not liable in that case). The applicant had unconditionally resigned from his previous post and was claiming damages for loss of the new post.

However, in the subsequent case of Kapfunde, the Court of Appeal held that the doctor is not liable for economic loss in this way, even if negligent:

Kapfunde v Abbey National & Daniel, Court of Appeal, 1998
A job applicant revealed in her health questionnaire that she had sickle cell anaemia, which had in the past led to her being absent from work. Dr Daniel, a GP providing medical services including pre-employment assessment, reported that she was likely to have higher than average absence. The company rejected her for the job. The court held Dr Daniel did not have a duty of care to the job applicant, only to the employer. (Even if there had been a duty, the GP was also held not to have been negligent.)

This case was before the Disability Discrimination Act. Now both the company and OH practitioner may have liabilities under the Equality Act (see OH practitioner liability under EqA). As to vicarious liability in civil law, the court held that the bank would not have been vicariously liable for the doctor’s negligence even if the doctor were liable, because the doctor was not an employee. However the issue discussed by the court was whether or not the doctor was an employee. The claimant did not argue that there could be vicarious liability for negligence of a self-employed doctor, but a claimant may now seek to argue this in the light of more recent cases such as Various claimants v Barclays Bank plc: see below Is an employer vicariously liable for negligence of an OH professional?

As regards the doctor not being liable to the job applicant in negligence, the Court of Appeal in Kapfunde drew an analogy with the House of Lords decision in X (Minors) v Bedfordshire CC which has now been superseded by the East Berks decision (see next heading), so its authority is somewhat weakened. There again, unlike those decisions Kapfunde related only to economic loss.

Job applicants: Physical harm

What about physical harm, if OH fails to warn of a health risk and of the need to consult the person’s GP? Firstly, whatever the legal position, a doctor is likely to feel under a moral obligation to inform the person of the risk.

As regards the legal position, it is very possible that OH practitioners owe a duty of care as regards physical harm. There are cases in the United States where OH doctors have been held liable to the individual for failing to diagnose medical conditions, both in annual health checks and in pre-employment examinations.

In Britain, the cardiologist in Hamed v Mills, Tottenham Hotspur & Cowie below (2015) at first tried to deny that he had a duty of care but later conceded that he did, ‘quite properly’ in the judge’s view. In that case a young football player suffered severe brain damage after a failure to warn him and his parents that he was at risk of hypertrophic cardiomyopathy (HCM). Also:

JD v East Berks Community Health, House of Lords, 2003
A doctor examining a child at the request of a local authority in a case of suspected child abuse owes a duty to the child (though not the parents), even though employed by and reporting to the local authority.

That House of Lords decision in East Berks has weakened the authority of a comment previously made by the House of Lords as regards a doctor instructed by an insurance company to examine an applicant for life insurance. The House of Lords commented ‘The doctor does not, by examining the applicant, come under any general duty of medical care to the applicant. He is under a duty not to damage the applicant in the course of the examination: but beyond that his duties are owed to the insurance company and not to the applicant’. That was in the case of X (Minors) v Bedfordshire CC 1995 , where psychiatrists instructed by a local authority to examine children in cases of suspected child abuse were held not to have a duty of care to the child or parent. However, that decision has been partly superseded by the East Berks case above which held there was a duty to the child.

The issue is only addressed to a limited extent in the English case of R v Croydon Health Authority, which suggests that so far as there is a duty (which the Court of Appeal did not consider) the courts may limit the loss for which the applicant can claim from the doctor, because of the employment context of the examination:

R v Croydon Health Authority, Court of Appeal [1998] P.I.Q.R. Q26
A radiologist who was negligent in reading a pre-employment X-ray was held liable to pay damages to a job applicant in respect of physical harm. He had failed to report to the OH physician evidence of pulmonary hypertension disclosed by the X ray. This affected her fitness to work (she would not have been given her new job had the condition been known) and also gave rise to particular risks associated with pregnancy. The claimant suffered medical problems when she later became pregnant. She argued – and the court accepted – that she would not have become pregnant had she been warned of the medical condition. The defendant admitted that it had breached a duty of care to the claimant and was liable for medical problems suffered in pregnancy.

The Court of Appeal held the defendant was not liable for other costs of the pregnancy, such as costs of bringing up the child. It said the obligations assumed by the radiologist making a pre-employment examination did not extend to the claimant’s private life. The court left open what the position would be had the admissions of liability not been made. Other damages were also awarded which were not disputed before the Court of Appeal – eg. for complications of a hysterectomy so far as they would probably not have occurred had diagnosis been earlier.

Liability to third parties, such as employees of contractors or members of the public?

It will depend on the Caparo test above. For example an OH practitioner’s duty may well extend to other people (apart from employees) on the site, such as contractors. Another example where the OH practitioner could be liable is an OH physician in the NHS who negligently passes a surgeon as fit to perform exposure prone procedures, such that a patient is infected with Hepatitis C.

As a general rule, there is no legal liability for the deliberate wrongful act of another adult, eg. a worker who persists in drinking and driving to and from work.

Palmer v Tees Health Authority, Court of Appeal, 1999
A mental patient known to be a danger to children brutalised and murdered a child. It was held that the hospital owed no duty of care to the child or her mother. The child had been a ‘random’ victim, and not identifiable.

Accordingly, an OH physician who fails to report that a driver has unstable insulin-dependent diabetes should not be liable to a pedestrian who is injured when the worker has a hypoglycaemic attack on the public road (though the employer may be vicariously liable for the driver, and the OH physician might be liable to the employer).

However, in a US case, Tarasoff v University of California (1976) a doctor knew that one of his patients had murderous intentions towards a particular young woman. She was indeed murdered and her parents sued the doctor. He was held liable for failing to warn her. It is possible that a British court would reach the same result in these circumstances, since the victim was identified (though see further below on disclosure in public interest).

Also, it is possible that an OH practitioner could be liable for failing to warn that someone is a risk to colleagues or, as mentioned above, perhaps to other groups such as patients.

Kent v Griffiths, Court of Appeal, 2000
An ambulance service was held liable to a patient for negligently failing to attend an emergency until 40 minutes after it had accepted a 999 call. There was no good reason for the delay. The doctor who called the ambulance gave evidence that had she known of the delay she would have advised the claimant’s husband to drive her to the hospital.

Apart from who duties are owed to, the Tarasoff case above raises the issue of breaching patient confidentiality in the public interest. OH practitioners are sometimes legally permitted – and quite possibly ethically required – to warn of a risk to others in the public interest despite lack of patient consent (see Public interest: Disclosure to protect others, and also Duty to disclose poor practice?). May the doctor or nurse also have a legal duty to disclose confidential information without consent in some circumstances? – see below.

See also above Tension with employer?

Is there ever a legal duty to breach confidence?

Avoiding potential civil liability often does not involve a conflict with patient confidentiality, but what if it would do? For example what if OH knows that someone driving other workers around is not fit to drive, the driver does not want it disclosed, and the situation is not one where simply refusing to report will see the worker taken off the job? The OH practitioner might disclose in the public interest in accordance GMC guidance: see Public interest: Disclosure to protect others. But if the OH practitioner prefers to follow the patient’s instructions and not disclose, could he be liable for, say, injuries to other workers arising from an accident which results?

This is not clear. In the St George’s Healthcare case below, the Court of Appeal considered that the GMC guidance can create an ethical obligation to disclose, and held it ‘arguable’ that there was also a legal obligation to disclose to the claimant genetic test results of her father (contrary to his wishes) which showed the claimant to be at risk. However some of the reasoning related particularly to genetic testing, given the way it shows information which of particular importance for a limited number of relatives. Outside of genetic testing, the case perhaps indicates some caution on the part of the courts, and that in considering whether such a legal duty to disclose is just and reasonable the courts would seriously consider policy issues, including what duties would be workable for medical practitioners. Further decisions will be required to clarify the position.

ABC v St George’s Healthcare NHS Trust, Court of Appeal 2017
A father was diagnosed with Huntington’s Disease. This meant each of his daughters, including the claimant who was pregnant, had a 50% chance of developing the condition. However he did not want them told. The claimant had her child and found out afterwards about her father’s illness, and that she had Huntington’s herself. This meant she was unlikely to be capable of caring for her child after middle age, and that the child too might be affected (it was too soon to test). She sued the hospital and others saying she should have been told earlier and would have had an abortion.

The Court of Appeal only had to decide whether her claim was arguable, so that it should proceed to full hearing. The court held yes it was. The defendants accepted there was sufficient proximity between claimant and defendants for a duty of care to arise. The issue was whether it was ‘arguably’ fair, just and reasonable to impose a duty (see Caparo above) in the light of the doctor’s normal duty of confidentiality to patients. The court considered (at para 23) that the GMC guidance was not limited to allowing disclosure but could create an ethical obligation to disclose, if the clinician conducts the requisite balancing exercise and concludes that it falls in favour of disclosure. However the question for the court was whether a breach of that obligation was actionable in law.

The court held that yes it was arguable that there was a legal duty to tell the daughter in the present case, given that it was genetic information. The court considered numerous policy issues as to whether the professional duty to disclose should also be a legal duty, such as trust of patients in doctors, and doctors facing the risk of being sued by someone whether they disclose or not. The court also considered (from para 42) the danger that a legal obligation could ‘open the floodgates’ in areas outside of genetic conditions, eg a patient refusing to tell sexual partners of an STD, or refusing to tell family and friends of a contagious disease. However the court said the genetic clinician is in a different position because only in genetics does the clinician acquire definite and critical information about a third party, often meaning the third party should become a patient.

Is an employer vicariously liable for negligence of an OH professional?

This page focuses mainly on liability of the OH professional. However the employer too may be vicariously liable for acts and omissions of the OH professional. See further the general discussion of Vicarious liability.

Vicarious liability: OH professional directly employed

The employer can clearly be vicariously liable where the OH professional is directly employed by the employer. An example:

Hamed v Mills, Tottenham Hotspur & Cowie, High Court, 2015
The claimant was a teenager signed up with the football club’s Youth Training Scheme and Football Academy, as a full-time apprentice. As with any new entrant to a football academy, the club’s doctor (who was an employee of the club) sent him for tests with a consultant cardiologist to check for risk of life-threatening heart disease, including hypertrophic cardiomyopathy (HCM). In a young athlete HCM can lead to death or severe brain damage. The latter happened in the claimant’s case. The tests by the cardiologist had raised suspicions, but the claimant and his parents were not warned of the risk. The cardiologist at first tried to deny that he had a duty of care, relying perhaps on Kapfunde above, but later conceded that he did to the judge’s approval. The cardiologist contended he had done enough to alert the club’s doctors to the possibility that the claimant might have a latent condition and that they should arrange more tests. The club’s doctor claimed the cardiologist did not do enough to alert her.

The court held both the cardiologist and the club’s doctor liable, the cardiologist being 30% to blame and the club’s doctor (and hence the football club) 70%. The club accepted that it owed a duty of care both as a result of the employer/employee relationship (a duty to take all reasonable steps to safeguard him from reasonably foreseeable risk of injury during the course of his employment), and as result of the doctor/patient relationship under the Bolam test above because the club was vicariously liable for acts and omissions of the doctor who was its employee.

Vicarious liability: OH professional not directly employed

Vicarious liability has been extended to some people who are not employees: see Vicarious liability>People other than employees. The leading case on this actually related to OH. In Various claimants v Barclays Bank below (2020) a bank was held not to be vicariously liable in civil law for alleged sexual abuse of young recruits by a self-employed doctor. The court said the question was whether the doctor was carrying on business on his own account or whether he was in a relationship akin to employment with the bank. Here he was carrying on a business on this own account, so the bank was not vicariously liable.

Various claimants v Barclays Bank plc, Supreme Court, 2020
The doctor was an independent contractor carrying out (mostly) pre-employment medical examinations for Barclays Bank, up to the mid-80s. He did so at his home where he had a consulting room, and the bank paid him a fee for each examination. Many of the bank recruits were females aged 15 or 16. He was alleged to have carried out sexual assaults, such as inappropriate breast examinations, and/or digital vaginal contact or penetration. The doctor died in 2009. He also did medical examinations for a different employer (a mining company) and an insurance company, and carried out sessions at local hospitals.

The Supreme Court held, reversing the courts below, that Barclays was not liable for the doctor’s actions. The question was whether the tortfeasor is carrying on business on his own account or whether he is in a relationship akin to employment with the defendant.

In doubtful cases, the five criteria used by the lower courts may be helpful in identifying a relationship which is sufficiently analogous to employment to make it fair, just and reasonable to impose vicarious liability. However the key will usually lie in understanding the details of the relationship. Where it is clear that the tortfeasor is carrying on his own independent business it is not necessary to consider the five criteria.

In the present case the doctor was in business on his own account, so the bank was not vicariously liable:

“Clearly, although Dr Bates was a part-time employee of the health service, he was not at any time an employee of the Bank. Nor, viewed objectively, was he anything close to an employee. He did, of course, do work for the Bank. The Bank made the arrangements for the examinations and sent him the forms to fill in. It therefore chose the questions to which it wanted answers. But the same would be true of many other people who did work for the Bank but were clearly independent contractors, ranging from the company hired to clean its windows to the auditors hired to audit its books. Dr Bates was not paid a retainer which might have obliged him to accept a certain number of referrals from the Bank. He was paid a fee for each report. He was free to refuse an offered examination should he wish to do so. He no doubt carried his own medical liability insurance, although this may not have covered him from liability for deliberate wrongdoing. He was in business on his own account as a medical practitioner with a portfolio of patients and clients. One of those clients was the Bank.”

The Supreme Court commented that the test for vicarious liability is not necessarily the same as for whether someone is a worker.

Note: see also Vicarious liability>People other than employees.

The Supreme Court in Barclays also quoted the summary of the principle by Lord Reed in Cox v Ministry of Justice (2016):

‘… a relationship other than one of employment is in principle capable of giving rise to vicarious liability where harm is wrongfully done by an individual who carries on activities as an integral part of the business activities carried on by a defendant and for its benefit (rather than his activities being entirely attributable to the conduct of a recognisably independent business of his own or of a third party), and where the commission of the wrongful act is a risk created by the defendant by assigning those activities to the individual in question.” (Emphasis added by the court in Barclays.)

In a later case on dentists, the Court of Appeal has downplayed the importance of whether the doctor etc appeared to be carrying on their activities as an integral part of the defendant’s business, when looked at by someone who did not know the contractual arrangements between them. In Hughes v Rattan a dental practice was held not to be vicariously liable for a dentist who, to a patient, would just appear to be one of the dentists at the practice:

Hughes v Rattan, Court of Appeal, 2022
The question was whether the dentist (Dr Rattan) running a dental practice was liable for alleged negligence of three (self-employed) Associate Dentists working in the practice. The Court of Appeal held Dr Rattan was in any event liable under a non-delegable duty of care, as being responsible for treatment to the patient under a Treatment Plan naming him (para 68-72).

It was therefore unnecessary to consider vicarious liability, but the Court of Appeal considered it anyway and said Dr Rattan was not vicariously liable for the Associate Dentists. Looking at the test in Cox quoted above, the Court of Appeal would have upheld the High Court decision that Dr Rattan was vicariously liable. The Associate Dentists were carrying on their activities as an integral part of Dr Rattan’s business and for its benefit, and were not conducting recognisably independent businesses of their own – taking ‘recognisable’ in this context to mean recognisable to someone with no knowledge of the contractual arrangements between Dr Rattan and the Associate Dentists. However following Barclays, said the Court of Appeal, the critical question now appeared to have reverted to whether the relationship of the alleged tortfeasor (the Associate Dentist) with the defendant (Dr Rattan) could properly be described as being ‘akin’ – or ‘analogous’ – to employment, with the focus being on the contractual arrangements between tortfeasor and defendant. The Court of Appeal also commented that it did not matter whether the Associate Dentists were ‘workers’.

The Court of Appeal held that the Barclays test for vicarious liability was not met in the present case, for reasons it set out in para 89. Particularly significant were that the Associate Dentists were free to work at the particular practice for as many or as few hours as they wished, and they were also free to work for other practice owners and business, and some in fact did so. (The relationship between Dr Rattan and the Associate Dentists was however closer to the ‘akin to employment’ line than the relationship in the Barclays case.)

Note: Dental Protection has said it is considering appealing the ruling on non-delegable duty of care to the Supreme Court. If it does so, the claimant may well also appeal on the issue of vicarious liability.

As to how this is likely to apply to OH practitioners generally, though it will depend on the individual facts:

  • Where a self-employed OH practitioner works for an OH provider as part of the latter’s business, and the OH provider contracts with the ultimate client employer, the OH provider is potentially vicariously liable for the OH practitioner but (subject to any appeal in Hughes v Hattan) the court may consider contractual arrangements between the practitioner and OH provider which are not apparent to the client employer.
  • Where an independent OH practitioner works directly for the ultimate client employer, it is less likely than might previously (before Barclays) have been thought that the employer will be vicariously liable.

Thus, the ultimate client employer will generally be vicariously liable for its own employees (above), but will often not be vicariously liable where it uses an independent OH practitioner. Any vicarious liability is in any event limited by the Kapfunde decision above under which neither the employer or doctor are liable for economic loss (failing to get the job) arising from negligence on the part of an OH doctor reviewing pre-employment questionnaires, at least where he did not see the individual. However an employer who is vicariously liable may be liable if negligence results in physical harm, such as the brain damage in the football case above, and could be liable for sexual abuse as in the Barclays case.

Also even though the employer is not vicariously liable, it may have a primary liability in some cases, eg a failure to check on the qualifications of an adviser, or to supervise. It might have been argued that Barclays was negligent because they didn’t insist on a chaperone.

Professional liability insurance does not cover criminal activity, which is why the claimants sued Barclays.

Note that vicarious liability is on the whole confined to the civil law, and the employer can be liable even without being negligent itself. The employer is absolutely liable for the negligence etc of the agent. It is not like criminal liability under the Health and Safety and Work Act 1974 where the employer may have a defence if it shows it took all reasonably practicable steps to avoid the exposure to risk, for example by checking a contractor’s competence.