For employers in the UK, understanding the duty of care they have in relation to the mental health of their employees is no longer optional. It is a legal obligation – and one that Employment Tribunals are increasingly holding businesses to account for.
Most employers genuinely do not set out to get this wrong. However, good intentions are not a defence against a Tribunal claim. What matters is what steps were taken, and critically, whether the employer acted when the warning signs were there rather than when it was too late.
In this blog, we look at three key cases that show exactly where employers have gone wrong, what the courts expect, and the practical steps you can take to make sure your business is on the right side of the law and ensure the welfare of your team.
What Does the Employers’ Mental Health Duty of Care Actually Require?
Before diving into the case law, it is worth being clear on what the law actually requires. Employers have a legal duty to protect the health, safety, and welfare of their employees under the Health and Safety at Work etc. Act 1974. Importantly, that duty extends to mental health, not just physical safety.
In addition, the Equality Act 2010 can protect individuals from discrimination on the grounds of their mental health. If an employee’s mental health condition qualifies as a disability ( a mental impairment that has a substantial and long-term adverse effect on day-to-day activities), employers are required to make reasonable adjustments to prevent individuals from being placed at a substantial disadvantage as a result of that condition. Employees must also not be treated less favourably because of the condition or subjected to unfavourable treatment because of something arising from the condition.
Furthermore, the Management of Health and Safety at Work Regulations 1999 require employers to carry out suitable and sufficient risk assessments in relation to the health and safety of their staff – and this includes assessing risks to mental health.
It is therefore important to comply with these requirements to avoid claims and reputational damage. The cases below show how this has played out in practice.
Case Law: Where Employers Have Gone Wrong
Each of the following cases offers a clear lesson as to the consequences of being aware of issues in the workplace and failing to act, or acting without properly accounting for an employee’s mental health
Walker v Northumberland County Council [1995]: The Landmark Case
“An employer owes a duty of care not to cause an employee psychiatric injury by the volume or character of the work the employee is required to perform.” – Colman J
This case changed the landscape in relation to employers’ duty of care in the UK by confirming that it extends to mental health as well as physical health. John Walker was a social work manager dealing with a growing caseload of child abuse cases. He raised concerns with his employer that the workload was unsustainable. Nothing changed, and in 1986 he suffered a nervous breakdown.
On his return to work, the employer promised additional support. That support never materialised. In fact, his workload increased. Less than a year later, he suffered a second, more severe breakdown and was ultimately dismissed on grounds of ill health.
The High Court found the employer liable. Crucially, the key issue was not simply that the work was stressful. It was that after the first nervous breakdown, the employer was clearly on notice of the impact of the workload on Mr Walker’s mental health, and whilst they made a commitment to help, they then did nothing to reduce the workload or otherwise support him.
What went wrong: The employer was informed of a problem, gave a commitment to act, and failed to follow through. Once an employer is aware of a risk to an employee’s mental health, inaction can be a breach of their duty of care.
Hatton v Sutherland [2002]: Setting the Framework
This Court of Appeal judgment heard four cases together and remains one of the most important authorities on employer liability for workplace stress. All four claimants had claimed they had psychiatric illness caused by workplace stress and their employers’ failure in their duty of care to support them. They had previously won their cases, but their employers appealed these decisions to the Court of Appeal.
The Court of Appeal considered whether psychiatric injury was reasonably foreseeable to each employer; whether the employers breached their duty of care towards the employees; and (3) whether any breach caused the harm suffered. Lady Justice Hale set out 16 practical propositions that courts still reference today.
Among the most important principles for employers to understand:
- Employers are generally entitled to assume employees can cope with normal job pressures, unless there is reason to think otherwise.
- There are no jobs that are inherently harmful to mental health. Liability always depends on foreseeability in each individual case.
- Indications of impending harm must be clear enough that a reasonable employer would feel compelled to act.
- Offering a confidential Employee Assistance Programme (EAP) with access to counselling reduces – but does not eliminate – the risk of a successful claim.
In one of the four cases, the appeal against a schoolteacher’s claim succeeded because her employer had been given no clear indication she was at risk. She had not raised any specific health concerns, and her workload was comparable to coping colleagues. The court found the harm was not reasonably foreseeable.
What this tells us: Employers cannot be expected to act on problems they genuinely had no way of knowing about. However, the flip side is equally important: if the signs are present, employers are expected to act. Turning a blind eye is not consistent with employers’ mental health duty of care.
Muir v AstraZeneca UK Ltd [2024]: Mental Health and Misconduct
This more recent case is particularly important because it goes beyond workload and stress, and into the territory of disciplinary processes – an area where employers frequently make costly mistakes.
Dr James Muir had worked for AstraZeneca since 1998 and had a history of depression and anxiety, which AstraZeneca was aware of. During a high-pressure project, colleagues raised concerns about his behaviour, describing forceful outbursts in meetings. The company investigated this, concluded his conduct amounted to bullying and harassment, and dismissed him without notice for gross misconduct.
The Employment Tribunal upheld his unfair dismissal, wrongful dismissal, and disability discrimination. This was because:
- Investigators knew about Dr Muir’s mental health conditions but did not explore whether they had contributed to the conduct under investigation.
- No occupational health referral was made to obtain advice on how these conditions might affect or influence conduct.
- There was no formal written complaint from any colleague regarding Dr Muir’s conduct, yet a formal disciplinary process was pursued.
- The appeal officer had, in the Tribunal’s words, “the perfect opportunity to remedy the earlier errors” but also failed to take his mental health into account.
The Tribunal was clear: the behaviour may not have been acceptable, but the response was disproportionate and ignored the impact of his mental health conditions entirely. The company should have intervened earlier, made an occupational health referral, and considered whether informal support could have resolved matters before escalating them to a formal disciplinary process.
What went wrong: AstraZeneca was aware of the disability, had evidence the employee was struggling, and nonetheless moved straight to dismissal without properly considering his mental health at any stage of the process. As this case confirms, if you are aware of a mental health condition, this must be carefully considered throughout any investigation or disciplinary procedure.
Meeting Your Mental Health Duty of Care: What Good Looks Like
The good news is that the case law is not just a series of cautionary tales. It is also a practical roadmap. Across these judgments, the courts consistently point to the same actions that responsible employers take. Here is what you should have in place.
1. Carry Out a Stress Risk Assessment
This is a legal requirement under the Management of Health and Safety at Work Regulations 1999 [The Management of Health and Safety at Work Regulations 1999 ], not an optional extra. Your assessment should identify any potential specific causes of workplace stress in your organisation and set out the steps you are taking to address them. Critically, it should be reviewed and updated regularly – not only when someone raises a problem.
2. Train Your Managers
In practice, most mental health issues at work are reported to a line manager before they reach HR. Training your managers on how to spot warning signs, have a supportive conversation, and recognise when to escalate matters, is the best way to ensure that employees receive the support they need.
3. Act Early, Not Late
Walker, Muir, and almost every case in this area share the a similar theme: the employer knew something was wrong and did not act quickly enough. An early conversation, an occupational health referral, or a temporary workload adjustment can often change the outcome. Prompt action is both the right thing to do and a sound legal protection.
4. Factor Mental Health Into Disciplinary Processes
If an employee has a known mental health condition, you should not set this aside when a conduct issue arises. You need to consider whether the condition may be connected to the behaviour in question, whether adjustments should be made to the process itself, and whether support should be offered before or alongside any formal action. As Muir v AstraZeneca demonstrates, a failure to do this can be very costly.
5. Do Not Rely on an EAP Alone
Providing an EAP is a positive step. However, as Hatton v Sutherland makes clear, pointing an employee to an EAP does not in itself fulfil your duty of care. Discussions should be held with the employee to understand exactly what they are struggling with and how you can support them in relation to this.
6. Document Everything
If you have taken steps to support an employee, record them. If a concern was raised and you responded, keep a written note of the response. If an occupational health referral was made, file the outcome and any subsequent report. Take notes of any meetings with employees to discuss support and adjustments. Thorough documentation demonstrates to a Tribunal that you took the matter seriously from the beginning – even if the situation did not resolve perfectly.
The Bottom Line
Employers’ duty of care in relation to their employees’ mental health is an important legal obligation and a key component of ensuring a flourishing workforce. The learnings from the cases above can help you to ensure you are supporting your employees in the right way and protecting their mental health.
With the Employment Rights Act 2025 now in force and Employment Tribunals facing a growing backlog of claims, there has never been a more important time to make sure your policies, processes, and people are prepared.
For more on what the law requires, take a look at our blog on employers’ obligations towards mental health at work [Employers’ obligations towards employees’ mental health at work – Thrive Law]. At Thrive, this is not just something that we instil within our procedures; it is embedded into the foundations of how our business operates. It is something we offer in our training programmes to ensure that every business has the opportunity to thrive.
Need Help Getting This Right?
At Thrive, we help employers across the UK understand their mental health duty of care, review their policies, and train their teams to handle these situations with confidence and compassion. Whether you have a specific situation to work through or simply want to make sure your business is in a strong position, we are here.
Get in touch at enquiries@thrivelaw.co.uk or call us on 0113 861 8101. We’d love to help.
