Hard work never hurt anybody.” That is what many of us were taught as children. But there is a limit - and Northumberland County Council was recently held by the High Court to have gone too far.

John Walker, a senior social worker employed by the council, had two mental breakdowns brought on by stress and overwork. He left his job after the second and then sued the council claiming that his health had been damaged as a result of excessive stress at work. He won; the public sector union Unison, which is supporting him, says he is looking for Pounds 250,000.

It is no less true for colleges than local authorities. Lecturers’ contracts of employment are being amended -talks between the Colleges’ Employers’ Forum and the National Association of Teachers in Further and Higher Education to resolve their two-year dispute continue at a snail’s pace.

Employers should specify what is regarded as a reasonable workload. Staff should ask to take the initiative by reporting to supervisors if operational demands exceed or fall below the target levels.

European-led legislation, such as the recent extension of maternity rights, is imposing increasing costs on employers. Many directors consider that stress is a fact of working life which everybody who works has to put up with. So what should they do following the decision in Mr Walker’s case?

Every employer has a legal duty to provide a safe system of work for his staff which means taking reasonable steps to prevent reasonably foreseeable risks.

If the employer fails to take the right steps, he is in breach of his duty of care and may become liable for negligence as there is now a statutory duty to make regular assessments of potential risks to employees’ health.

The dispute between Mr Walker and Northumberland confirms that employers must look after the mental health of staff members in the same way as their physical health. Just as an employer may be held liable for negligence if his employees have to use dangerous equipment, so he may be liable if employees are submitted to excessive and unreasonable stress at work.

Mr Walker’s case indicates what is excessive stress and what is unreasonable.

His workload as a social worker grew markedly because of a large increase in the local population; the resources available to him did not. Job pressure intensified following publicity about perceived failings of some social workers in child abuse cases.

After his breakdown, Mr Walker - who had no previous history of mental disorder - returned to work to find that paperwork had built up in his absence and that the extra help he had been promised did not materialise. He then suffered a second breakdown, threw in the towel and left. The council was fully aware of the pressures on Mr Walker.

Stress at work occurs typically when an employee has no control either over the demands made on him or her, or over the resources required to meet those demands. This lack of control explains why stress is a much more serious medical problem at a relatively junior level than is sometimes supposed.

In another on-going case, a hospital doctor is claiming that he has suffered psychological trauma caused by excessively long working hours. His contract required him to be at work or on call for an average of 88 hours a week.

But sometimes employers can pre-empt problems. Take, for example, a case against HM Customs and Excise last year. An employee sued following a mental breakdown but the court held that the department was not negligent. It had sent him on sick leave after his breakdown, moved him to an easier job and then gave him early retirement when it became clear that he could still not cope.

The Health and Safety Executive is set to publish guidelines for employers on how to deal with stress at work pressures on employees are regularly reviewed as part of general health and safety risk assessments.

Workloads are monitored and investigation follows if employees regularly stay late or fail to take their holiday allowance.

Complaints about excessive workload are taken seriously. Action is taken to match resources with demands, and managers are trained to recognise stress problems and deal with them effectively.

Some jobs carry an unavoidable degree of stress and it is now common for this to be made clear to applicants.

Formal screening may be appropriate Psychometric testing can show those who could cope with a high level of stress and those who could crack under pressure. The Post Office has adopted this method as part of an integrated approach to work-related stress.

These steps make sound financial sense. The HSE has estimated that 40 million working days are lost in Britain each year as a result of stress-related illness, and that up to 60 per cent of all absences from work are caused by stress. This costs employers billions of pounds every year and wastes countless hours of management time. Mr Walker’s case is yet another reason why employers cannot afford to ignore work-related stress.

Contracts of employment should be amended. Employers should take care to specify what is regarded as a reasonable workload and staff should take the initiative by reporting to supervisors if operational demands exceed or fall below the target levels.

Ronnie Fox is the senior partner of City law firm Fox Williams, specialising in employment and partnership issues