Does the law allow employees to work late?

Sarah Garner outlines the specific UK rules and regulations governing limitations on working weeks

UK employees have the longest working week compared to workers in other EU countries, according to TUC research. A study conducted by French researchers, meanwhile, found that working long hours can be directly associated with poor health and mental illness, as well as increasing the risk of having a stroke by 50 per cent.

If a company employs staff, there are limits on the amount of time they can be expected to work. This can be a complicated issue, so employers should take care to ensure they do not breach the relevant regulations.

Under the Working Time Regulations, staff should not normally have to work more than 48 hours per week on average. To calculate the average, the hours are generally based on the hours worked over the past 17 weeks.

While most employees cannot be forced to work an average of more than 48 hours a week, they can opt out of this limitation if they wish to do so, allowing them to work longer hours. They must do this voluntarily, and they should set out their decision in writing. A worker can also agree to opt out for a certain period of time – for example, during a busy time for a business – or indefinitely.

Employers cannot introduce a collective agreement with their entire staff that states they will all opt out of the 48-hour limit.  While employers are allowed to ask if specific workers would be willing to do it, this must be discussed individually. If a worker doesn’t want to opt out, they cannot be dismissed or treated adversely as a result.

A worker who has chosen to opt out is allowed to change their mind at any time but will not be obliged to work longer than an average of 48 hours a week. To cancel their opt-out, they need to give their employers at least seven days’ notice. The notice period may be longer if they agreed to this when initially opting out. At this stage, employers can set it to a maximum of three months. Employers cannot force their staff to cancel an opt-out agreement.


There are exceptions on both sides of the Working Time Regulations. Some workers can always be made to work more than an average 48 hours in a week, and some workers are not allowed to work more than 48 hours a week on average even if they want to.  

The 48-hour weekly work limitation does not apply to:

  • security and surveillance roles;
  • domestic servants in private households;
  • workers on board sea transport or sea-fishing vessels;
  • mobile workers on vessels on inland waterways;
  • the emergency services (except trainee doctors) and the armed forces, in certain situations;
  • positions where 24-hour staffing is needed; or
  • roles where the worker is in control of their time and their working hours are not measured (for example, self-employed people or senior managers).

Workers cannot opt out of the 48-hour working week if they are:

  • airline workers;
  • staff members on ships or boats;
  • road transport workers or other operators of vehicles covered by EU drivers’ hours regulations; or
  • security guards on vehicles with high-value loads.

Calculating working hours

People can work for more than 48 hours in any given week as long as the amount of time they work over a 17-week period averages at 48 hours or less. Annual leave does not count as part of the reference period (for example, if a worker is taking annual leave or is off sick, this will not reduce the average).

For the purposes of calculating average working hours, you should include time spent on:

  • training relating to the worker’s role;
  • paid overtime or involuntary unpaid overtime;
  • travel time for the worker where travel is part of their job (eg travelling salespeople);
  • working lunches;
  • being available if needed (‘on call’) while remaining in the workplace; and
  • anything else that is stated as ‘working time’ under a contract.

Sarah Garner is a solicitor at DAS Law

Disclaimer: This information is for general guidance regarding rights and responsibilities and is not formal legal advice as no lawyer-client relationship has been created