Night work rules

If you are a night worker, your employer must make sure you work no more than an average of eight hours in each 24-hour period, and must offer you a free health assessment before you start nights and regularly after that. You cannot opt out of the night work average the way you can opt out of the 48-hour week. These rules come from the Working Time Regulations 1998 and apply across the NHS, care, police staff, prisons and other public services that run around the clock.

Who is a night worker

Night time is a period set by law or by agreement that covers the middle of the night. If your contract does not define it, the default period in the regulations applies. The gov.uk night working page gives the exact hours.

You count as a night worker if you regularly work a set minimum number of hours of your shift during night time. “Regularly” can mean working nights as a normal part of your rota, not every week. A nurse on a rotating rota that includes a block of nights every month is likely to be a night worker. Someone who does an occasional night shift to cover sickness may not be.

If the definition is unclear for your job, ask HR how your employer applies it, because it decides whether the limit and health assessment apply to you.

The eight-hour average limit

Night workers must not work more than an average of eight hours in each 24 hours. The average is normally worked out over a 17-week reference period, the same as the 48-hour week, and can be changed by a collective or workforce agreement.

This is an average, so 12-hour night shifts are lawful as long as enough days off are included. Say you work three 12-hour nights a week and nothing else. That is 36 hours in a seven-day week, which averages a little over five hours in each 24 hours, well within the limit.

For night work that involves special hazards or heavy physical or mental strain, the eight-hour limit applies to each 24 hours with no averaging. Employers should identify these roles through their risk assessment.

Unlike the 48-hour weekly limit, you cannot sign away the night work limit. There are some exceptions for particular jobs and for workers in roles needing continuity of service, such as hospitals and care, where employers can vary the limit through an agreement and give compensatory rest. Check whether your employer relies on an exception.

Health assessments

Before you start night work, your employer must offer a free health assessment, and then offer one regularly after that. This is usually a questionnaire reviewed by occupational health, with a follow-up if anything is flagged. You do not have to accept it.

If a doctor advises that night work is affecting your health, your employer should move you to suitable day work where possible. Records of assessments must be kept.

Pregnancy, young workers and health

If you are pregnant or breastfeeding and a doctor or midwife certifies that night work is a risk to your health, your employer must offer suitable day work on the same terms. If none is available, you should be suspended on full pay. The pregnancy rights guide covers the wider risk assessment.

Young workers under 18 are generally not allowed to work at night, with limited exceptions such as in hospitals. The gov.uk page sets out the detail.

If you have a disability or long-term health condition made worse by nights, stopping night shifts can be a reasonable adjustment. See the reasonable adjustments guide.

Rest and breaks on nights

The standard rest rules apply to night shifts too: a 20-minute break if your shift is over six hours, 11 hours’ rest between working days, and 24 hours off each week or 48 hours each fortnight. In hospitals and care settings employers can vary these if they give compensatory rest. The rest breaks guide explains them, and the working nights guide covers sleep, health and practical routines.

Pay for nights

The law does not require extra pay for night work, but your pay must not fall below the minimum wage. Most public sector terms pay an enhancement. In the NHS, Agenda for Change unsocial hours payments cover nights; see the NHS unsocial hours guide. Council, police staff and prison terms have their own allowances.

If your employer is not following the rules

Raise it with your manager and occupational health, then use the grievance procedure if needed. The Health and Safety Executive and councils enforce the night work limits. If you suffer a detriment for asserting these rights, a tribunal claim is possible after ACAS early conciliation, within the six-month time limit that applies since 1 October 2026. Your union can help with rota disputes.