Employers' primary liability - Stress at work claims

Learning Outcomes

This article examines employers' primary liability for stress at work claims, including:

• the core legal principles governing employers’ primary liability in stress at work and psychiatric injury claims
• the scope and content of the employer’s common law duty of care for employees’ mental health, and how it links to a safe system of work
• how courts assess employee-specific foreseeability, including application of the Hatton guidelines and typical exam fact patterns
• what amounts to breach of duty, the range of reasonable steps an employer should take once on notice, and how this is tested in SQE1-style questions
• the causation requirements in psychiatric injury claims, including the “but for” test, material contribution, and the impact of pre-existing vulnerability or non-work stressors
• the necessity for a medically recognised psychiatric injury, and why mere stress or upset is insufficient for recovery
• the relevance of non-delegable duties, risk management practices, and health and safety regulations in setting the standard of care
• how courts approach divisible and indivisible injuries, apportionment, contributory negligence, and common traps for SQE1 candidates when applying these principles to problem questions

SQE1 Syllabus

For SQE1, you are required to understand the legal framework for employers' liability in stress at work claims, with a focus on the following syllabus points:

• the scope and content of the employer’s common law duty of care regarding employees’ mental health and stress at work
• the requirements for foreseeability and the Hatton guidelines
• how breach of duty and causation are established in psychiatric injury claims
• the distinction between stress at work claims and other psychiatric injury claims
• practical steps employers should take to manage risk and reduce liability
• the need for a medically recognised psychiatric illness (not mere stress or upset)
• the employer’s non-delegable duty to provide a safe system of work, including risk assessment, training and supervision
• defences and damages issues, including contributory negligence, material contribution, and apportionment for divisible injury
• the relevance of health and safety regulations to the standard of care (civil liability for breach generally excluded, but regulations remain evidentially relevant)

Test Your Knowledge

Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.

1. What is the threshold question for establishing an employer’s duty of care in a stress at work claim?
2. Name two factors that may make psychiatric injury from workplace stress foreseeable to an employer.
3. What is the significance of the Hatton guidelines in stress at work claims?
4. True or false? An employer is always liable if an employee suffers psychiatric injury due to stress at work.
5. What must a claimant prove to establish causation in a stress at work claim?

Introduction

Employers owe a duty to take reasonable care for the health and safety of their employees. This duty extends to both physical and mental health, including the risk of psychiatric injury caused by workplace stress. Claims for stress at work are a specific category of employers’ liability and have distinct legal requirements compared to other psychiatric injury claims. A claimant must demonstrate a medically recognised psychiatric disorder; ordinary stress, anxiety or upset, without such diagnosis, is insufficient. Unlike the primary/secondary victim framework used for shock-induced psychiatric harm in accident cases, workplace stress claims are framed as breaches of the employer’s primary duty to provide a safe system of work, with foreseeability assessed by reference to what the employer knew or ought reasonably to have known about the individual employee.

Key Term: duty of care
The legal obligation on employers to take reasonable steps to protect employees from foreseeable harm, including psychiatric injury from workplace stress.

Key Term: recognised psychiatric injury
A medically recognised psychiatric illness diagnosed by an appropriate expert (e.g. depression, anxiety disorder, PTSD). Mere stress, grief or worry is not actionable.

The Employer’s Duty of Care and Stress at Work

Employers must provide a safe system of work, competent staff, adequate equipment, and a safe workplace. This duty is personal and non-delegable. The duty to protect employees from psychiatric harm caused by workplace stress is part of the duty to provide a safe system of work. The standard is one of reasonable care, not a guarantee of safety. Reasonable employers are expected to plan and supervise work to minimise foreseeable risks, including psychosocial risks arising from workload, working patterns, and management practices. The court considers the magnitude and likelihood of risk, the gravity of potential harm, and the cost and practicality of precautions.

Core features of the common law duty include:

• competent staff (including training and supervision of managers whose conduct can generate or mitigate stress risks)
• adequate plant and equipment (including tools that affect workload or time pressure)
• a safe system of work (systems, instructions, risk assessments and supervision designed to prevent foreseeable harm, including stress-related harm)
• safe premises (including the workplace environment, and third-party sites where employees work)

Key Term: safe system of work
The arrangements, procedures, and supervision put in place by an employer to ensure employees can perform their work safely, including minimising risks of stress-related harm.

Key Term: non-delegable duty
A personal duty on employers to take reasonable care for employees’ safety that cannot be discharged by entrusting tasks to others. Employers must see that reasonable care is taken, whether by employees or independent contractors.

Foreseeability and the Hatton Guidelines

The threshold for liability in stress at work claims is foreseeability. The employer will only be liable if it was reasonably foreseeable that the employee would suffer psychiatric injury due to workplace stress. Foreseeability is assessed in the context of the particular employee. A generally stressful job environment does not by itself establish foreseeability of psychiatric injury to a particular individual. Employers are not required to be medical experts or to make intrusive enquiries into private life; they are judged by what they knew or should have known acting reasonably.

Key Term: foreseeability
The ability to predict or expect that a particular type of harm might occur in the circumstances.

The leading authority is Hatton v Sutherland [2002], which established practical guidelines for determining foreseeability and liability in stress at work claims. These guidelines have been approved by the House of Lords and remain central for SQE1.

Key Term: Hatton guidelines
Practical guidance from Hatton v Sutherland on foreseeability, reasonable steps and causation in stress at work claims, focusing on what the employer knew or ought to have known about the individual employee.

The Hatton Guidelines (Summary)

1. Foreseeability of harm: The key question is whether injury to health through stress at work was reasonably foreseeable.
2. Knowledge of the employer: Foreseeability depends on what the employer knew or ought to have known about the individual employee.
3. Assumption of normal coping ability: Employers are generally entitled to assume employees can withstand normal pressures of the job unless made aware of a particular problem or vulnerability.
4. Signs of stress: Factors that may make harm foreseeable include high workloads, repeated absences, complaints about stress, or previous episodes of psychiatric illness.
5. Reasonable steps: If harm is foreseeable, the employer must take reasonable steps to prevent it. What is reasonable depends on the circumstances.
6. Causation: The claimant must prove that the employer’s breach of duty caused or materially contributed to the psychiatric injury.

Additional points to note:

• Signs of impending harm can include sustained long hours, deteriorating performance, tearfulness, irritability, sleep issues reported to management, or warnings from occupational health or a GP. Repeated sickness absence for stress-related reasons and explicit complaints are strong indicators.
• The nature and demands of the job, the employee’s workload and control, and any known vulnerabilities are all relevant. Where an employer knows of a particular vulnerability, foreseeability is more readily established.
• Employers are not required to restructure their business or create new roles if that would be unreasonable; the steps required are those a reasonable employer would take in the circumstances.

Worked Example 1.1

Scenario:
An employee, Alex, repeatedly tells his manager that he is overwhelmed by his workload and has taken several periods of sick leave for stress. No changes are made to his duties. Alex later suffers a breakdown and is diagnosed with depression.

Answer:
The employer was on notice of Alex’s difficulties. Psychiatric injury was reasonably foreseeable. The employer failed to take reasonable steps to reduce Alex’s workload. The breach of duty materially contributed to Alex’s illness. Alex is likely to succeed in a stress at work claim.

Worked Example 1.2

Scenario:
Priya works in a busy call centre. She has no history of mental health problems and has not complained about her workload. She suffers a sudden breakdown after a period of increased pressure.

Answer:
There were no warning signs or complaints. The employer was entitled to assume Priya could cope with normal pressures. Psychiatric injury was not foreseeable. The employer is unlikely to be liable.

Worked Example 1.3

Scenario:
Ben consistently records 60–70-hour weeks on timesheets over several months. His manager praises his commitment but notices more frequent mistakes and terse emails. Ben has never complained. HR receives an email from Ben referencing “burnout” and asking for help, but no action is taken for eight weeks, during which Ben’s workload increases further. Ben is later diagnosed with an anxiety disorder.

Answer:
The combination of objectively excessive hours, deteriorating performance, behavioural changes, and an explicit plea for help would make psychiatric harm reasonably foreseeable. The delay in responding, coupled with increased workload, indicates a failure to take timely, reasonable steps. Breach and foreseeability are likely established.

Breach of Duty and Reasonable Steps

If psychiatric injury is foreseeable, the employer must take reasonable steps to prevent harm. What is reasonable depends on the size of the business, the nature of the work, the resources available, and the practicality and effectiveness of proposed measures. Reasonable steps may include adjusting workloads, reallocating tasks or deadlines, authorising leave, providing training or supervision, instituting closer managerial support, making a prompt referral to occupational health, or offering access to counselling or an employee assistance programme. In some cases, temporary redeployment or flexible working may be appropriate. Employers should consult the employee, implement agreed measures, and monitor outcomes. The duty is one of reasonable care: it does not require eliminating all stress or guaranteeing a particular outcome.

Relevant considerations in assessing breach include:

• the magnitude and likelihood of risk (e.g. ongoing high workloads and clear warning signs)
• the gravity of potential harm (psychiatric illness can be serious and debilitating)
• the cost and practicality of precautions (low-cost steps such as workload reviews and OH referrals should be taken promptly; more intrusive or costly measures may still be required if risk is high)
• the employer’s systems (risk assessments, training for managers on identifying and addressing stress, supervision and monitoring arrangements)
• the speed and adequacy of the response once on notice

Key Term: breach of duty
The failure of an employer to meet the standard of care required by law, resulting in a risk of harm to the employee.

Employers are not expected to micro-manage all aspects of an employee’s life or anticipate purely personal stressors unrelated to work. However, once put on notice of a risk of psychiatric injury from work-related factors, they must act reasonably to mitigate that risk. Offering support services can be a reasonable step, but simply signposting a helpline without addressing workload or management practices is unlikely to be sufficient where those are the main stressors.

Worked Example 1.4

Scenario:
Chloe reports rising anxiety due to conflicting deadlines and insufficient staffing. Her employer immediately meets with her, reduces her caseload by 30%, reassigns deadlines, arranges weekly check-ins, and refers her to occupational health. Changes are implemented within two weeks and reviewed monthly. Despite this, Chloe later develops depression.

Answer:
Psychiatric harm was foreseeable once Chloe raised concerns, but the employer took prompt, targeted, and practical steps (workload reduction, supervision, OH referral, monitoring). On these facts, the employer likely met the standard of reasonable care. The occurrence of injury does not itself prove breach; liability is unlikely.

Causation in Stress at Work Claims

The claimant must prove that the employer’s breach of duty caused or materially contributed to the psychiatric injury. This can be challenging if there are multiple causes, such as personal problems outside work. The usual “but for” test applies: would the claimant have suffered the psychiatric injury but for the employer’s breach? Where multiple causes interact and indivisibility makes “but for” analysis impractical, the claimant may succeed by showing the breach made a material (more than negligible) contribution to the injury.

Key Term: causation
The requirement to show that the employer’s breach of duty was a factual cause of the employee’s psychiatric injury.

If the injury is divisible (e.g. distinct episodes that can be medically separated), damages may be apportioned to reflect work-related and non-work-related causes. If the injury is indivisible (e.g. a single psychiatric disorder with multiple contributing factors), the employer may be liable for the whole of the injury if their breach made a material contribution. Once foreseeability is established, the employer takes the employee as they find them; a particular susceptibility does not reduce the scope of damage, although it may be relevant to foreseeability.

Contributory negligence may reduce damages where an employee unreasonably fails to engage with reasonable protective measures, such as repeatedly refusing occupational health assessments or persistently rejecting feasible adjustments, provided those refusals were not themselves a symptom of the psychiatric condition.

If there is doubt about timing, evidence of escalating work-related stress (complaints, absence records, contemporaneous emails) is often central. Expert medical evidence is required to diagnose the psychiatric disorder and to address causation and divisibility.

Worked Example 1.5

Scenario:
Sam has a history of anxiety. He tells his employer about his condition and requests a reduction in workload. The employer ignores his request. Sam later suffers a relapse.

Answer:
The employer was aware of Sam’s vulnerability. Psychiatric injury was foreseeable. The employer’s failure to act materially contributed to Sam’s relapse. The employer is likely to be liable, even though Sam had a pre-existing condition.

Worked Example 1.6

Scenario:
Maya experiences a relationship breakdown and also faces chronic understaffing at work. She complains to her manager about workload and takes two short periods of sick leave. No adjustments are made. Maya is later diagnosed with depression. Medical evidence indicates both the breakup and workload contributed, and the condition is indivisible.

Answer:
Foreseeability arose once Maya complained and had stress-related absences. The employer’s inaction is a breach. Given an indivisible injury with multiple causes, liability follows if the breach made a material contribution. Maya can recover full damages for the depressive disorder, subject to any deduction for contributory negligence if appropriate. If medical evidence supported divisibility (e.g. two distinct episodes), apportionment might be considered.

Practical Risk Management for Employers

Employers should:

• Monitor workloads and working hours.
• Respond promptly to complaints or signs of stress.
• Provide access to support services.
• Adjust duties or provide additional resources where appropriate.
• Keep records of actions taken.
• Train managers to identify and respond to stress indicators, and to conduct supportive one-to-one meetings.
• Carry out and review stress risk assessments, and implement appropriate controls.
• Refer promptly to occupational health when warning signs arise, and act on recommendations where reasonable.
• Ensure policies on absence management, performance, and flexible working are applied consistently and sensitively.
• Evaluate whether repeated overtime, persistent deadline clashes, or staffing gaps indicate structural risk requiring organisational changes.

Compliance with health and safety regulations does not in itself create a separate civil cause of action for breach, but remains highly relevant evidence of what a reasonable employer should do. Following accepted standards, conducting risk assessments, and implementing practicable precautions are all persuasive in showing that reasonable care has been taken.

Key Term: material contribution
Where an employer’s breach of duty is one of several factors that significantly contributed to the employee’s psychiatric injury.

Summary

Key Point Checklist

This article has covered the following key knowledge points:

• The employer’s duty of care includes protecting employees from foreseeable psychiatric injury caused by workplace stress.
• A medically recognised psychiatric illness is required; mere stress or upset is not actionable.
• Foreseeability is the threshold for liability—employers are entitled to assume normal coping ability unless put on notice by complaints, absences, or other warning signs.
• The Hatton guidelines set out the key principles for stress at work claims and focus on what the employer knew or ought to have known about the individual employee.
• Breach of duty occurs if the employer fails to take reasonable steps after becoming aware of a risk; the duty is one of reasonable care, not a guarantee of safety.
• Causation requires proof that breach caused or materially contributed to the psychiatric injury; divisible injuries may be apportioned, indivisible injuries may attract full liability where there is material contribution.
• Contributory negligence may reduce damages where an employee unreasonably fails to engage with reasonable protective measures.
• Employers should implement proactive risk management: monitor workloads and hours, train managers, assess risks, make timely OH referrals, adjust workloads, and record decisions.
• Health and safety regulations inform the standard of care even though civil claims for their breach are generally excluded.

Key Terms and Concepts

• duty of care
• safe system of work
• foreseeability
• Hatton guidelines
• recognised psychiatric injury
• non-delegable duty
• breach of duty
• causation
• material contribution