If an employee agrees to work more than the limit imposed by the Working Time Regulations 1998, can the employer be held liable if the employee becomes ill as a result of working long hours?

The Working Time Regulations 1998 (SI 1998/1833) set a 48-hour limit on average weekly working hours, but workers can opt out of this limit by signing an agreement. However, in addition to their obligations under the Working Time Regulations 1998, employers have a common law duty to take reasonable care of the health and safety of their employees. This includes taking care to avoid a risk to an employee's mental health. If an employer knows or could reasonably be expected to foresee that there is a risk to an individual employee's health as a result of their long working hours, it has a duty to take steps to prevent that risk. An employer could be held liable for a breach of its duty of care, even where the employee has voluntarily opted out of the statutory limit on average weekly working hours.