Last reviewed 15 June 2022

Is an employer under a duty to protect an employee from psychiatric injury due to workplace stress where it is reasonably foreseeable that the employee is at risk of suffering from that kind of harm? Barrister Robert Spicer reports on a recent case.

Workplace stress

In the recent case of Mackenzie v AA plc, the High Court has given judgment on the foreseeability of workplace stress.

The facts, in summary, were that in August 2017, M, a former executive chairman and CEO of AA, was summarily dismissed for gross misconduct. This followed an incident in which he assaulted a colleague after drinking heavily at a strategy away day.

M brought a number of claims against AA plc including a claim for compensation for personal injury. The basis of the claim was that his conduct had been the consequence of psychiatric illness caused by stress at work. His argument was that the board and senior management knew that he had become overstressed because of his workload and this had affected his physical and mental health. This had culminated in severe anxiety and depression. M claimed that the assault and his dismissal had been caused by AA plc’s failure to take reasonable care for his health and safety.

AA plc applied for summary judgment, arguing that the claim had no realistic prospect of success. The High Court ruled as follows.

  • M had been unable to provide any evidence that the employer knew or ought to have known that, because of stress at work, there was a risk that he would develop a psychiatric injury.

  • M’s expert evidence tended to support the conclusion that the employer could not have foreseen such an injury.

  • The claim was dismissed because there was no real prospect of success.

  • The key principles which apply to workplace stress claims include the requirement that the psychiatric injury must have been foreseen by the employer. In this case it was not.

  • It was not enough to show that the employer knew that the worker had too much work to do or that they were vulnerable to stress because of overwork.

  • Stress in itself was not enough. It must be shown that the employer knew or ought to have known that there was a real risk of injury because of stress at work.

  • Employers were entitled to assume that workers could withstand the normal pressures of their work.

  • Employers only had a duty to act when the indications of imminent harm were clear enough for any reasonable employer to realise that it should do so.

  • An employer is not generally obliged to make searching or intrusive enquiries and may take communication from workers at face value.

Previous cases

The case of Mackenzie v AA plc can be seen as an application of the leading case on workplace stress, which is Sutherland v Hatton (2002). In that case, the Court of Appeal heard four appeals by employers against compensation awards made to workers who had suffered stress-induced psychiatric illness. The Court of Appeal made points which were applied in the Mackenzie case. It also stated the following.

  • Where an employee wishes to remain in a stressful job, and the only alternative was demotion or dismissal, an employer is not in breach of duty in allowing the employee to continue.

  • Indications of impending harm to health at work must be clear enough to show an employer that action should be taken.

  • An employer is in breach of duty where it fails to take reasonable steps bearing in mind the size of the risk, the gravity of the harm, the cost of preventing the harm and any justification for taking the risk.

  • No type of work should be regarded as intrinsically dangerous to mental health.

  • Employers who offer confidential counselling advice services, with access to treatment, are unlikely to be found in breach of their duty of care in relation to workplace stress.

  • The amount of compensation will be reduced to take account of pre-existing conditions or the chance that the employee would have become ill in any event.

Another example is the case of Dickins v O2 plc (2008). The facts, in outline, were that D was employed by O as a secretary. In 2001, she was promoted to regulatory finance manager. She became exhausted and stressed and was unable to work. She did not receive help. Her request to move to a less stressful job did not succeed. She was advised to contact the in-house counselling service. She did not do so because she was already receiving counselling on a private basis.

In June 2002, D was signed off work, suffering from anxiety and depression. She did not return to work and she claimed compensation from O. At first instance the claim succeeded. The court ruled that it was clear that D had been under extreme stress, that she should have been granted time off work and should have been immediately referred to occupational health. O appealed to the Court of Appeal which dismissed the appeal and made the following points.

  • The evidence was clear that the employer had received a clear indication of impending illness.

  • Counselling services were not a panacea by which employers could discharge their duty of care in all cases.

  • D had tipped over the edge from stress to a complete breakdown because nothing significant had been done to recognise and address her need for a rest.


In general, employers need to be aware that risks of psychiatric injury to workers have been increased during the pandemic. Current case law is relatively clear in stating that workers have a very high hurdle to overcome in making workplace stress claims. In appropriate cases, applications for summary judgment, as in the Mackenzie case, may prevent such claims at an early stage.