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What are the key rules governing working time?

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The Working Time Regulations 1998 (SI 1998/1833) (WTR 1998), is the key legislation governing working time in the UK. This Guide covers the key provisions, except for annual leave.

Meaning of working time

The concept of "working time" applies to the WTR 1998 rules on the average maximum working week, night working, rest periods and rest breaks. It's important to remember that the National Minimum Wage Regulations may have a different definition of working time. Working time under the WTR 1998 is defined as any period during which the worker is doing all of the following:

  • working;
  • carrying out their duties;
  • at the employer's disposal;
  • Any period during which the worker is receiving "relevant training"; and
  • Any additional period which is agreed in a relevant agreement to be working time.

The following will normally be treated as working time:

  • Paid overtime and some unpaid overtime
  • Time spent waiting or "on call" at the workplace (or at another place chosen by the employer), even if the worker is allowed to sleep.
  • Responding to telephone calls while on call (at any location).
  • Travelling to incidents while on call.
  • Travel time where travel is part of the job, such as travelling sales reps. This can include travelling to the first appointment of the day, and returning home from the last appointment of the day, for mobile workers.
  • Working lunches.
  • Work taken home at the request of the employer.
  • Attending work-related training.
  • Other time that is treated as "working time" under a relevant agreement.

Bear in mind however that there may be exceptions. The test is whether the worker is working, carrying out their duties, and at the employer's disposal (unless they are receiving relevant training or there is a relevant agreement which defines the time as working time).

The following activities will not normally be considered working time:

  • Rest breaks including lunch breaks and coffee breaks.
  • Daily and weekly rest periods.
  • Annual leave.
  • Time spent "on call" if the worker is not required to be at a particular place.
  • Travelling to the workplace, unless the travel is undertaken following "booking on" or reporting to an assigned depot or booking-on point.
  • Attending work-related social events.
  • Unpaid overtime undertaken voluntarily (as will be the case with many managers).
  • Attending evening classes or day-release classes that are not a requirement of the job.
  • Working from home voluntarily.
  • Responding to telephone calls voluntarily out of hours, including when travelling.
  • These activities will not normally be considered working time because the worker does not fulfil one or more of the criteria of working, carrying out their duties, and being at the employer's disposal.

If an employee fulfils their duties by working from home or elsewhere, as an alternative to working at their office or usual workplace, the time spent working will usually be working time. If, however, the employee voluntarily takes work home, perhaps to complete a project, then this will not usually fall within working time. This is because the worker is not "at the employer’s disposal" if they can, in practice, choose not to work at that time.

If the employee has to travel to somewhere other than their workplace then it appears that a journey during the working day would fall within the definition of working time, while a journey in the employee's "own time" would not. Time spent commuting to the employee's usual place of work would therefore not usually be viewed as working time. The employer has no control over how long the worker spends commuting as this will depend on where the employee lives.

48-hour weekly limit

Unless an exemption applies, a worker's average working time (including all overtime and time spent working for others) must not exceed 48 hours per week.

An employer must take all reasonable steps, in keeping with the need to protect health and safety, to ensure that this limit is complied with. Failure to do so is a criminal offence punishable with a potentially unlimited fine.

Although workers can work more than 48 hours in any particular week, the weekly average over the "reference period" (by default, 17 weeks) must not exceed 48 hours.

All workers are covered by the 48 hour limit unless they are expressly excluded. The main exemptions are:

  • Workers in particular sectors excluded or partially excluded from the WTR 1998; and
  • Workers who have validly "opted out" (see more information below).

Opting out of the 48-hour week

The limit on average working hours does not apply if the employer has "obtained the worker's agreement in writing" to perform work in excess of the limit. This is generally referred to as an "opt-out agreement". The opt-out agreement can last for a fixed period or indefinitely. Any opted-out worker can cancel the opt out by giving at least seven days' notice unless the opt-out agreement provides for longer notice (which cannot exceed three months).

Employers should also consider the following:

  • Even if a worker has agreed to opt out of the limits, he cannot be required to work excessively long hours if this creates a reasonably foreseeable risk to his or others health and safety.
  • Employers must keep records covering the last two years showing which workers have opted out.
  • The opt-out should specify that the worker agrees to disapply the statutory 48-hour limit and not simply state that they agree to work more than 48 hours. If applicable, the opt-out agreement may need to vary the contract of employment by specifying new working hours.
  • Some employers include an opt-out in job offer letters or in the contract of employment itself. However, this practice creates a risk of the employee suggesting that opting out of the limit was a requirement not a genuine option.
  • Employers pressurising workers to sign an opt-out or victimising anyone for refusing to do so risk unlawfully subjecting the worker to a detriment.
  • An employer can refuse to accept a worker's request to opt out.
  • Although it is unlawful to dismiss a worker or otherwise victimise them for refusing to sign an opt-out or for opting back in, there is currently no prohibition on refusing to employ someone unless they opt out.

There is not requirement to aggregate hours worked for different employers for the purposes of calculating average weekly working time. However, government guidance interprets WTR 1998 as requiring all working time to be counted, not just time worked for a particular employer.

If a worker has a second job, an employer should ask the worker to consider signing an opt-out agreement if the total time worked exceeds 48 hours a week. If the worker does not wish to do so, the worker should consider reducing their hours to comply with the 48-hour limit.

Risk-averse employers should ask workers to confirm if they work for anyone else,  or consider prohibiting workers from working for others without the employer's written consent.

Rest periods and rest breaks

Subject to certain exemptions, the WTR 1998 provides that workers are entitled to:

  • A daily rest period of not less than 11 consecutive hours in each 24-hour period during which they work for their employer.
  • A weekly rest period of not less than 24 hours' uninterrupted rest in each seven-day period during which they work for their employer or, at the employer's choice, either:
    • Two uninterrupted rest periods of not less than 24 hours in each 14-day period; or
    • One uninterrupted rest period of not less than 48 hours in each 14-day period.
  • A rest break of an uninterrupted period of not less than 20 minutes if the worker's working time is more than six hours. The worker is entitled to spend their rest break away from their workstation.
  • Adequate rest breaks where the employer's working pattern puts a worker's health and safety at risk, in particular because the work is monotonous, or the work-rate is predetermined. This may involve providing further short breaks in addition to the usual daily and weekly rest periods and breaks, but the length of these breaks is not specified.

The entitlements to daily and weekly rest periods, daily 20-minute rest breaks and adequate rest breaks do not apply to:

  • Workers in excluded or partially excluded sectors.
  • Workers whose working time is unmeasured, such as controlling directors.
  • shift workers as follows:
    • Where the shift worker changes shift and cannot take a daily or weekly rest period between the end of one shift and the start of the next one.
    • Where the worker's activities are split up over the day, as may be the case with some cleaning staff.

Shift workers must, wherever possible, be allowed to take an equivalent period of compensatory rest if they have not had the benefit of their entitlement.

Employers must ensure that workers can take their rest periods or rest breaks but are not required to force workers to take them. Workers can elect to work additional hours by forgoing their rest entitlements under the WTR 1998, provided that:

  • The employer does not breach the 48-hour average weekly limit or the rules on night working.
  • There is no additional foreseeable risk to health and safety.

A worker can only bring a claim for breach of their entitlements to rest periods and rest breaks where the employer "has refused to permit him to exercise" the rights to rest. It follows that, if there has been no such refusal by the employer, and the employee is working voluntarily, there can be no claim.

Night work

The WTR 1998 have special provisions for night workers, which limit their shifts and require employers to offer regular health assessments and transfer night workers to day work if advised to do so by a doctor. These limits are in addition to the limit on average weekly working time.

Limits on night work do not apply to:

  • Workers in particular sectors excluded or partially excluded from the WTR 1998, including aviation, road transport, sea fishing and merchant shipping. In these cases, limits on working time are contained in sector-specific EU Directives and the domestic regulations implementing them.
  • The police, emergency services and armed forces, to the extent that the requirements of those services inevitably conflict with the relevant provisions of the WTR 1998.
  • Domestic servants in a private household.
  • Workers with unmeasured time, such as some autonomous decision-makers.
  • Mobile workers not already subject to a sector-specific exclusion.

In most cases, even if the limits on night hours do not apply, employers must remember to carry out regular health assessments and to monitor working hours.

There is no scope for individual workers to opt out of the night limits. However, employers may make a collective or workforce agreement to modify or exclude these limits. Provided that any union agreement is made in accordance with agreed procedures and is incorporated into workers' contracts it will be binding on all workers in relevant grades, even if they are not members of the union.

Special cases

The WTR 1998 recognise that some types of work cannot easily be reconciled with the limits on night work or the entitlements to rest breaks.

Accordingly, regulation 21 identifies a number of special categories of worker ("special case" workers). The limits on night work and the entitlements to rest breaks and daily and weekly rest periods do not apply to these workers, although they should be granted compensatory rest "wherever possible". The requirement to give health assessments to night workers is unaffected.

Special case workers remain subject to the 48-hour limit on average weekly working time, but the reference period for calculating average working time is automatically extended from 17 to 26 weeks.

The special cases are as follows:

  • Where the worker's activities are such that their home and workplace are "distant from one another" or the worker has a number of different workplaces that are distant from one another. There is no definition of "distant", but offshore workers are expressly included and it would probably also cover anyone whose time spent travelling to and from work forms a significant proportion of their time away from home.
  • Where the worker is "engaged in security and surveillance activities" requiring a permanent presence in order to protect property and people. This may include security guards and caretakers.
  • Where the worker's "activities involve the need for continuity of service or production" such as:
    • services relating to the reception, treatment or care provided by hospitals, residential institutions and prisons (thus covering most nursing and medical staff based in hospitals);
    • work at docks or airports;
    • press, radio, TV, postal and telecommunication services and civil protection services;
    • gas, water and electricity production, transmission and distribution, household refuse collection and incineration;
    • industries in which work cannot be interrupted on technical grounds;
    • research and development activities;
    • agriculture; and
    • the carriage of passengers on urban transport services.

(not an exhaustive list- the test is whether "the worker's activities involve the need for continuity of service or production")

  • Where there is a foreseeable surge of activity, such as in agriculture, tourism and postal services.
  • Where the worker's activities are affected by unusual and/or unforeseen and/or exceptional circumstances which are beyond the employer's control or which could not have been avoided despite the exercise of all due care, or by an accident or the imminent risk of an accident.
  • Where a rail transport worker's activities are "intermittent", where the worker works on board trains, or where the worker's activities are linked to transport timetables and to ensuring the continuity and regularity of traffic.

Young workers

The WTR 1998 contain special provisions covering young workers. A young worker is a worker aged under 18 but over compulsory school age. In England and Wales compulsory school age ends on the last Friday in June of the academic year in which they turn 16. In Scotland, it ends on their 16th birthday.

Young workers may not generally work more than 40 hours in any week. In contrast to adult workers, whose weekly working hours are averaged over a reference period, there are no averaging provisions for young workers. The 40-hour limit applies to each individual week.

Young workers may not generally work more than eight hours in any day.

For workers with more than one employer, the daily and weekly working time limits are an aggregate of work done for all employers.

A young worker is generally entitled to not less than 12 consecutive hours' rest in each 24-hour period during which they work for their employer. This rest period may be interrupted in the case of activities involving periods of work that are split up over the day or are of short duration.

A young worker is generally entitled to 48 consecutive hours rest in each seven-day period during which they work for their employer. This rest period may be interrupted in the case of activities involving periods of work that are split up over the day or are of short duration. It may also be reduced where this is justified by technical or organisational reasons, but not to less than 36 consecutive hours.

If the young worker's daily working time is more than four and a half hours they are entitled to a rest break of at least 30 minutes, away from their workstation.

Employers must generally ensure that young workers do not work during the "restricted period", which is the period between 10.00 pm and 6.00 am or (where the contract requires them to work after 10.00 pm), the period between 11.00 pm and 7.00 am. This means that, in general, young workers cannot be "night workers".

There is an exception for work of a temporary nature which no adult is available to perform, that must be performed immediately, and which is occasioned by unusual and unforseeable circumstances beyond the employer's control, or exceptional events whose consequences could not have been avoided. Compensatory rest must be given within three weeks if the young worker works during what would otherwise have been a rest period or rest break.

The daily and weekly work limit may be disapplied where necessary to maintain continuity of service or production or to respond to a surge in demand for a product, if no adult worker is available and the young worker is not adversely affected.

There are less restrictive night work rules for young workers in certain sectors including healthcare, cultural, artistic, sporting or advertising activities, agriculture, retail, hospitality, catering, postal and newspaper delivery services and bakeries. These are subject to the need for adult supervision and compensatory rest where appropriate.

Workers covered by the WTR 1998

The WTR 1998 only protect "workers", defined as all those working under either of the following:

  • A contract of employment.
  • Any other contract whereby the individual undertakes to perform personally any work or services for the other party to the contract, where the other party is not by virtue of the contract a client or customer of any profession or business undertaking carried on by the individual.

This includes employees, temporary workers and freelancers, but not the self-employed genuinely pursuing a business activity on their own account.

Enforcement and penalties

There are a wide range of sanctions available against an employer under the WTR 1998, depending on the breach in question. These include:

  • A potentially unlimited criminal fine. In England and Wales, a potentially unlimited fine applies regardless of whether the offence is tried on summary conviction or on indictment. In Scotland, if charged on indictment, the fine is potentially unlimited, and if charged on summary conviction subject to a maximum statutory penalty.
  • "Improvement" or "prohibition" notices issued by the HSE or local authority inspectors, with potentially unlimited fines and up to two years' imprisonment for directors on conviction on indictment if such a notice is not complied with. On summary conviction, in England and Wales, the penalty for failure to comply is a potentially unlimited fine and up to three months' in prison, or in Scotland a maximum statutory fine and up to three months' in prison.
  • Compensation for workers in the employment tribunals.
  • Agreements being rendered unenforceable.

Automatically unfair dismissal and detriment

All workers (but not job applicants) are protected from being dismissed or subjected to a detriment by their employer on the grounds that the worker:

  • Refused (or proposed to refuse) to work longer than the prescribed limits on working time.
  • Refused (or proposed to refuse) to work when entitled to a rest period or break or to forgo annual leave.
  • Failed to sign a workforce agreement or to enter into, vary or extend any other agreement under the WTR 1998 (such as an opt-out agreement).
  • Performed (or proposed to perform) activities as a workforce representative or as a candidate for election as a workforce representative.
  • Brought proceedings to enforce a right under the WTR 1998, or alleged in good faith that their employer had infringed such a right.

Workers who are not employees are not entitled to the protection of unfair dismissal law. However, they may claim that the termination of their contract constituted a detriment.

Employees will be regarded as automatically unfairly dismissed where the reason or principal reason for dismissal is that they refused (or proposed to refuse) to:

  • Comply with a requirement which their employer imposed (or proposed to impose) in contravention of the WTR 1998.
  • Forgo a right conferred by the WTR 1998.


If you need guidance on any of the above matters, we are here to help.  Please do not hesitate to contact Martin Cornforth on 01636 558343, or email: