By Stuart Snape, Partner at Graham Coffey & Co. Solicitors
Workplace health and safety law operates on a principle that appears straightforward: employers must take reasonable steps to protect employees and others affected by their operations. In practice, the boundaries of this responsibility are far less clear. Modern work environments involve shared premises, remote roles, outsourced services, and overlapping operational control. Understanding where employer liability begins and ends requires close attention to legislation, workplace arrangements, and the distribution of risk.
The legal foundation of workplace liability
The Health and Safety at Work etc. Act 1974 places a duty on employers to ensure, so far as is reasonably practicable, the health, safety and welfare of their employees and others who may be affected by their activities. This includes contractors, visitors and the general public.
The Management of Health and Safety at Work Regulations 1999 build on this duty by requiring employers to assess risks, appoint competent people to manage them, and coordinate with others operating in the same workplace. Employers must also provide clear information and instructions to workers from outside organisations whose work interacts with their own.
These rules do not create exclusive responsibility. Instead, they impose shared and overlapping duties where multiple parties are involved.
Shared workspaces and overlapping duties
In environments such as construction sites, logistics hubs or co-working offices, employers are legally required to cooperate and coordinate with others to manage shared risks. As set out in HSE guidance, this duty applies even where employers have no direct relationship with each other.
Control over premises may be split between landlords, tenants, and facilities managers. But contractual arrangements do not override statutory obligations. If a hazard exists in a common area or arises from another organisation’s activities, an employer must still engage with others to reduce the risk. Liability may be shared based on who had practical control and the ability to act.
Vicarious liability and coworker negligence
Employers can be held liable for negligent acts committed by employees during the course of their employment. This principle, known as vicarious liability, applies even when the employer was not directly at fault. The courts focus on whether the conduct was closely connected to the employee’s duties.
In health and safety terms, this means an employer may be liable if one employee causes harm to another through careless or unauthorised behaviour, provided it was still part of their role. In Mohamud v WM Morrison Supermarkets plc [2016], the UK Supreme Court held an employer liable where an assault was closely linked to the employee’s duties. By contrast, acts that fall completely outside work responsibilities may fall beyond the employer’s liability.
This reinforces the need for appropriate training, supervision, and a working culture that discourages dangerous behaviour.
More on vicarious liability is explained by DavidsonMorris.
Independent contractors and non-delegable duties
Employers are generally not liable for the actions of independent contractors. However, liability can still arise where the employer retains control over the premises or has a non-delegable duty, meaning a responsibility that cannot be outsourced. This often applies where the work involves inherent risks or where the employer is expected to take personal responsibility for safety, regardless of who performs the task.
Due diligence is essential when selecting and managing contractors. Employers must check competence, communicate risks clearly, and monitor safety standards throughout the work. Simply handing off responsibility to a contractor is not always a valid defence.
Occupiers’ liability and control of premises
Under the Occupiers’ Liability Act 1957, those in control of premises owe a duty of care to lawful visitors. This includes employees, contractors, and anyone lawfully present on site. The occupier is not necessarily the legal owner, but the person or entity with control over the area.
In multi-occupier sites, courts assess who had control over the space where the injury occurred and whether they could have identified or corrected the risk. Where control is shared, liability may be divided. Employers must be aware of risks not just within their own workspaces but in communal or transitional areas their workers use.
Legal boundaries in complex workplaces
Complex sites such as construction projects, hospitals or commercial premises often involve multiple parties with overlapping obligations. On construction sites, for example, the CDM Regulations 2015 divide responsibility between the client, principal contractor, designers, and individual contractors. Each must plan and manage health and safety in a coordinated way.
If a failure occurs due to poor coordination – a missing risk assessment, a hazard left unaddressed, or unclear communication – liability can extend across multiple organisations. Courts will examine actual practices, not just contracts, when determining who was responsible.
Overlapping liability and contributory fault
Where several parties contribute to a workplace injury, liability may be apportioned. One employer may have failed to act on a known risk, while another may have failed to warn staff. Courts may also reduce damages under the principle of contributory negligence if the injured party’s own conduct played a role, for example, failing to follow safety instructions.
Shared responsibility is not only foreseeable but expected. The law places an active duty on employers to identify where their responsibilities intersect with others and to take steps to manage risks jointly. The HSE’s guidance on cooperation makes clear that overlapping obligations require active communication and shared planning.
Where the line is drawn
There is no fixed boundary where workplace liability begins or ends. It depends on context, control, and communication. Statutory duties are shaped by how workplaces function in practice, not by contractual definitions alone. As work environments become more integrated, employers must actively manage their responsibilities, particularly in relation to shared spaces, subcontracted work, and joint operations.
Liability is not only about fault after the fact. It is about foresight, coordination, and clear systems that prevent harm from occurring in the first place.
Photo by Alexander Grey on Unsplash
