Compulsory overtime

09 July 2019

In addition to normal working hours, employers may require their staff to work compulsory overtime. Unlike ‘voluntary’ overtime, compulsory overtime is a contractual obligation which clearly states that the employee is required to work additional hours, often on a regular basis. Just as employers must include accurate detail of normal working hours in the main terms of the employment contract (see working time regulations), they must also include reasonable detail of expected compulsory overtime. It is the duty of the employer to make staff aware that these hours will always be provided and, as such, they are effectively normal working hours that must be factored into an employee’s weekly or monthly schedule.

Holiday pay entitlement

Any additional hours worked as compulsory overtime must be included in the employee’s statutory holiday pay calculations. Employers must ensure that their current holiday pay calculations are in line with the relevant legislation and case law that protects employee rights regarding compulsory overtime and holiday pay entitlement. Failure to do so may result in a tribunal claim against the employer.

Limits to working hours

Although an employer is within their rights to include a compulsory overtime clause as part of the employment contract, they cannot legally ask employees to work longer than 48 hours on average in any given week. However, employees over 18 may choose to ‘opt out’ of the 48-hour week. The employer is legally allowed to ask the employee to opt out in order to work additional hours, but the employee cannot be sacked or treated unfairly if they refuse this request.

The law behind compulsory overtime

The Employment Rights Act 1996 and Working Time Regulations 1998 include the provision for holiday pay in relation to compulsory overtime. The Employment Rights Act 1996 also requires employers to include detail of working hours as part of the statement of main terms. Best practice regarding compulsory overtime in relation to holiday pay entitlement was established following a 2004 Court of Appeal case, Bamsey v. Albion.


  • Employers are legally required to include accurate detail of compulsory overtime within the main terms of the employment contract.
  • Any additional hours worked as compulsory overtime must be calculated as part of an employee’s holiday pay.
  • It is illegal for an employer to force a member of staff to work longer than 48 hours on average in any given week.

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