UK Legal Working Hours Explained

The legal working hours rules in the UK should form an important part of the knowledge base of anyone responsible for organising and overseeing the working hours of members of staff. The following comprehensive guide for employers, HR personnel and line managers looks at the law on working hours, including rest periods and rest breaks, together with some of the consequences of falling foul of the rules in relation to these requirements.

 

What is the law on working hours in the UK?

All workers have certain minimum statutory rights when it comes to legal working hours, as set out under the Working Time Regulations (WTR) 1998. These Regulations broadly implement the Working Time Directive, a piece of EU legislation introduced back in 1993, where the WTR still apply to UK law, even though the UK has now left the European Union.

The purpose behind the EU directive was to ensure that all workers, in the interests of their health and safety, do not undertake too many hours of work each week, and benefit from adequate rest periods and breaks. The WTR therefore makes provision for maximum weekly working hours, as well as for breaks both between and during shifts worked.

 

How many hours can an employee work per week?

Under the WTR 1998, an individual cannot usually work more than 48 hours each week on average in the UK. This means that workers have the right to work no more than this average maximum weekly limit, where Regulation 4(1) of the WTR (which makes provision for the maximum weekly working time) states that subject to Regulation 5, an employee’s working time, including overtime worked, in any reference period which is applicable in their case shall not exceed an average of 48 hours for each 7-day period.

Regulation 4(2) goes on to state that an employer shall take all reasonable steps, in keeping with the need to protect the health and safety of their staff, to ensure that this limit is complied with in the case of each person employed by them in relation to whom it applies.

 

Opting out of the limit on legal working hours

Regulation 5 of the WTR (which makes provision for agreement to exclude the maximum weekly working time limit) states that the limit specified in Regulation 4(1) shall not apply in relation to anyone who has agreed in writing with the employer that it should not apply.

In these cases, provided the employer complies with certain requirements, an adult worker can lawfully opt out of the maximum weekly working time limit, where any written agreement can either relate to a specified period or apply indefinitely. However, a worker can cancel an opt-out agreement at any time, provided they give the employer the prescribed notice. This will depend on what was agreed, but should be no more than 3 months. If the agreement is silent on the issue of notice, this notice will be just 7 days.

The requirements to be met by the employer in this context are that they maintain up-to-date records identifying each opted-out worker, together with any terms on which the worker agreed that the limit should not apply and the hours undertaken during each reference period since the agreement came into effect for up to 2 years. The employer must also provide access to those records on request to any relevant health and safety official.

Additionally, under Regulation 9 of the WTR, the employer is under a statutory duty to keep records which are adequate to show whether the limits on legal working hours specified in other parts of the Regulations have being complied with in the case of each worker in relation to whom they apply, again for a period of 2 years from the date on which they were made. However, there is no explicit obligation on employers to keep any records to show compliance with daily or weekly rest periods or breaks discussed further below.

 

How to calculate weekly working hours

When it comes to calculating weekly working hours for the purposes of the legal working hours’ limit — where a person’s working time, including overtime, in any reference period which is applicable in their case shall not exceed an average of 48 hours for each 7 days — a worker’s average working time for each 7 days during a reference period shall be determined under Regulation 4(6) of the WTR according to the formula: A + B over C.

“A” represents the aggregate number of hours comprised in a person’s working time during the course of their reference period, while “B” represents the aggregate number of hours for the period beginning immediately after the end of the reference period and ending when the number of days in that further period on which they have worked equals the number of excluded days during the reference period. “Excluded days” in this context typically mean days comprised in any period of statutory annual leave, or sick leave and maternity leave, taken by the worker. Finally, “C” is the number of weeks in their reference period.

 

What is the reference period?

When it comes to what is classed as the reference period for working time purposes, under Regulation 4(3) of the WTR, a 17-week reference period will usually apply.

In circumstances where someone has worked for their employer for less than 17 weeks, the applicable reference period will be the period that has elapsed since they started work for that employer. If there is a collective or other workforce agreement in place which specifies a different reference period, that period will apply instead. There are also special cases where a different reference period will apply, for example, trainee doctors have a 26-week reference period, while offshore oil and gas workers have a 52-week reference period.

However, in all cases, an individual can work more than 48 hours in any given week, provided the weekly average over the applicable reference period is less than 48 hours. The only exception to this rule is if a worker is aged under 18, where their working hours cannot be averaged out. These workers cannot work more than 40 hours in any one week.

 

Exceptions to the legal working hours’ rules

Under the WTR 1998, there are limited exceptions to the 48-hour weekly limit on legal working hours, where staff can be required to work more than 48 hours a week if:

• they work in a job where 24-hour staffing is required, such as in a prison or hospital
• they work in a security and surveillance role, such as a caretaker or security guard
• they are in the armed forces or emergency services
• they are a domestic servant in a private household
• they work in either the road, rail, sea or air transport sectors
• they work as a seafarer, fisherman or worker on vessels on inland waterways
• they work in circumstances where working time is not measured and the person is in control, for example, as a managing executive with autonomous decision-making powers.

 

WTR rules on rest breaks

All workers have the right to minimum daily and weekly rest breaks under the WTR 1998.

Under Regulation 10 (which makes provision for daily rest), adult workers are entitled to at least 11 consecutive hours’ rest in each 24-hour period or no less than 12 hours for under 18s. Under Regulation 11 of the WTR (which makes provision for weekly rest periods), adult workers are also entitled to one uninterrupted rest period of at least 24 hours each week, or at least 48 hours each fortnight, or no less than 48 hours each week for under 18s.

Finally, when it comes to rest breaks, under Regulation 12 of the WTR (which makes provision for daily rest breaks), adult workers are entitled to one uninterrupted 20 minute rest break during any shift worked of more than 6 hours, although any collective agreement or other workforce agreement may make different provision. Under 18s are entitled to a 30 minute rest break in any shift worked of more than 4.5 hours.

Importantly, for those workers where the 48-hour maximum working week does not apply, such as where 24-hour staffing is required, they are still entitled to adequate rest breaks.

 

WTR rules for night workers

Regulation 6(1) of the WTR (which makes provision for the length of night work) states that a night worker’s normal hours of work in any reference period applicable to them shall not exceed an average of 8 hours for each 24-hour period. As with other workers, the reference period for night workers will typically be calculated over 17 weeks.

However, special rules apply to night workers, where Regulation 6(7) provides that if night work gives rise to workplace hazards, or any heavy physical or mental strain, the employer must ensure that any shift undertaken by a worker is not actually longer than 8 in 24 hours.  The work of a night worker will be regarded as involving special hazards, or heavy physical or mental strain, if this has been identified in either any collective agreement or other workforce agreement, or recognised in any risk assessment undertaken by the employer.

In the context of night work, the employer must also offer free health assessments to new night-shift workers and on a regular basis, as appropriate, moving forward, keeping records of these assessments and the hours worked. If a worker is found to have health problems related to night working, the employer must offer suitable daytime work if at all possible.

 

Risks for employers

It is important for those responsible for organising and overseeing the working hours of staff to fully understand the rules on legal working hours to ensure that employers do not fall foul of the law. This is because there can be serious consequences of doing so. Any employer who fails to comply with the relevant requirements under the WTR 1998 will be guilty of an offence, liable on conviction to a fine. A worker may also lodge a WTR complaint before the employment tribunal for an award of compensation.

If there is a risk that staff are likely to work more than the legal working hours allowed, the employer should either ask staff to sign an opt-out agreement, where permitted, or reduce their weekly hours to meet the 48-hour limit. In most cases, employers can ask staff to opt out of the maximum number of weekly working hours, although there are statutory exceptions to these rules, including night workers and certain industry sector staff where it would be unsafe to allow longer hours. This must also be the worker’s choice, where an employer cannot dismiss an employee, or treat them unfairly, for any refusal to do so.

However, when staff are regularly working overtime in the workplace, or long and complex shift patterns, it is easy for employers to lose track of the hours undertaken. As such, it is also important for those responsible for the working hours of staff to keep careful records. These records will not only help to discharge the statutory record-keeping obligations under the WTR, but help the employer to ensure that staff remain with the legal limits.

In relation to record-keeping, the administrative burden on employers created by the WTR 1998 has recently been reduced by amendments made by the Employment Rights (Amendment, Revocation and Transitional Provision) Regulations 2023 (in force from 1 January 2024). The 2023 Regulations amend the WTR to explicitly state that employers no longer need to record each worker’s daily working hours if they are able to demonstrate compliance without doing so. The new legislation amending the WTR also states that the records “may be created, maintained and kept in such manner and format as the employer reasonably thinks fit.” This means that reductions can potentially be made to the record-keeping regimes currently in place for employers, although the changes do not rule out the fact that employers must still be able to produce documentary proof of legal working hours.

 

Need assistance?

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Legal working hours FAQs

Is it legal to work over 12 hours a day UK?

As the Working Time Regulations 1998 provide that adult workers are entitled to at least 11 consecutive hours rest in each 24-hour period, this means that it is possible for someone to work 13 hours a day in the UK.

Is working 60 hours a week legal UK?

A UK worker may undertake 60 hours in a week if either their average weekly working limit is no more than 48 hours over a 17-week reference period, or they have opted out of the limit on legal working hours.

What is the longest shift you can legally work?

The regulations around legal working hours require that there should be a break of 11 consecutive hours between each shift which, in theory, means that someone can work a 13-hour shift, provided they have sufficient rest breaks during this time.

What are the laws on working hours UK?

The laws on working hours in the UK are set out under the Working Time Regulations 1998 where, the maximum average weekly working limit is currently 48 hours, unless a worker opts out of this limit via agreement in writing.

 
Last updated: 9 December 2023