HR & Workforce · Best Practice · Pre-Construction

Working Time Opt-Out Agreement

A voluntary agreement signed by a worker consenting to work more than 48 hours per week.

Last reviewed: 29 March 2026 — This guide reflects UK law as of this date. Working Time Regs 1998 remains current with no amendments enacted as of 29 March 2026. Next scheduled review: 29 March 2027.

Legal basis	Working Time Regulations 1998, Regulation 5 (individual opt-out from the 48-hour maximum working week)
Weekly limit	48-hour average calculated over a 17-week reference period (extended to 26 weeks for construction workers by collective or workforce agreement)
Opt-out requirements	Must be in writing, must be voluntary, and the worker must be able to cancel the opt-out on not more than 7 days' notice (or such longer period as agreed, up to 3 months)
Unfair dismissal	Dismissing a worker for refusing to sign an opt-out agreement is automatically unfair under the Employment Rights Act 1996
Night workers	Maximum 8 hours per shift for night workers (between 11pm and 6am) — the opt-out does NOT apply to the night work limit
Rest entitlements	The opt-out does NOT exempt the employer from providing daily rest (11 hours), weekly rest (24 hours), or in-work rest breaks (20 minutes after 6 hours)

1. Working Time Opt-Out

The working time opt-out agreement is a document used to manage long hours on construction sites where project demands may require workers to exceed the standard 48-hour average working week. The Working Time Regulations 1998 set a maximum average working week of 48 hours, calculated over a reference period of 17 weeks (or 26 weeks in construction where a collective or workforce agreement is in place). Regulation 5 permits individual workers to voluntarily agree to opt out of this limit, provided the agreement is in writing and the worker is free to cancel it.

It is essential to understand that the opt-out relates solely to the 48-hour weekly average limit. It does not remove the employer's duty of care under the Health and Safety at Work etc. Act 1974 or the Management of Health and Safety at Work Regulations 1999. Even where a worker has signed an opt-out, the employer retains an obligation to manage the risks associated with fatigue, including assessing whether excessive working hours are affecting the worker's health, safety, or ability to perform their duties safely. Construction is a safety-critical environment, and fatigued workers operating plant, working at height, or performing lifting operations present a serious risk to themselves and others.

The opt-out does not exempt the employer from providing the daily rest period of 11 consecutive hours in every 24-hour period, the weekly rest period of 24 consecutive hours in every 7-day period (or 48 hours in every 14-day period), or the in-work rest break of 20 minutes where the working day exceeds 6 hours. Night workers are subject to a separate maximum of 8 hours per shift, and this limit cannot be opted out of. Dismissing or subjecting a worker to detriment for refusing to sign an opt-out agreement is automatically unfair under the Employment Rights Act 1996.

Never present the opt-out as a condition of employment

The opt-out must be genuinely voluntary. It must never be presented as a condition of employment, a condition of site access, or a requirement for being offered overtime. If a worker feels that refusing to sign will result in them losing their job, not being offered work, or being treated less favourably, the agreement is not voluntary and may be unenforceable. The worker must be informed of their right to cancel the opt-out at any time by giving written notice. Pressuring workers to sign opt-out agreements exposes the employer to claims for automatically unfair dismissal and regulatory enforcement action.

2. Content

The working time opt-out agreement must include the following information. The agreement should be a standalone document, separate from the employment contract, to reinforce that signing it is voluntary.

Field	Detail
Worker name	Full name of the worker who is agreeing to opt out of the 48-hour average weekly working time limit
Employer	The legal name of the employing company or organisation
Date	The date on which the agreement is signed — this establishes when the opt-out takes effect
Agreement text	A clear statement that the worker agrees to opt out of the maximum 48-hour average working week as provided by Regulation 4(1) of the Working Time Regulations 1998, in accordance with Regulation 5
Voluntary statement	An explicit confirmation that the worker is signing voluntarily, has not been pressured or coerced, and understands that refusing to sign will not result in any detriment to their employment
Duration	Whether the opt-out is for an indefinite period or a specified period. If for a specified period, the end date must be stated
Notice to cancel	A statement confirming the worker's right to cancel the opt-out at any time by giving written notice. The notice period must be stated and must not exceed 3 months (7 days is typical in construction)
Worker signature	The worker's handwritten signature and date, confirming their voluntary agreement to the opt-out
Employer signature	A signature from an authorised representative of the employer, confirming receipt of the signed agreement
Retention	The employer must retain the signed original for the duration of the worker's employment and for a minimum of 2 years after the employment ends. A copy must be given to the worker

3. Common Mistakes

Including the opt-out in the standard employment contract

Embedding the working time opt-out within the body of the employment contract undermines the requirement for the opt-out to be voluntary. If a worker must sign the employment contract to accept the job, and the opt-out is part of that contract, the worker has no genuine choice about whether to opt out. The opt-out must be a separate, standalone document that is presented to the worker independently of the employment contract. The worker must be told clearly that signing the opt-out is optional and that not signing it will have no effect on their employment, pay, or access to overtime. Employment tribunals have found opt-out agreements to be invalid where they were presented as part of a bundle of employment documents that the worker was required to sign on their first day.

Not informing workers of their right to cancel the opt-out

The Working Time Regulations 1998 give every worker who has signed an opt-out the right to cancel it by giving written notice to the employer. The notice period must not exceed 3 months, and 7 days is the standard in most construction contracts. Many employers fail to inform workers of this right, either at the point of signing or at any point afterwards. The cancellation right must be clearly stated in the opt-out agreement itself, and the worker must understand that they can withdraw their consent at any time without suffering any detriment. If the agreement does not include a cancellation provision, or if the worker was not made aware of their right to cancel, the opt-out may be unenforceable.

4. Frequently Asked Questions

Can young workers under 18 sign a working time opt-out?▾

No. Young workers (those aged 15 to 17 who are above compulsory school age but under 18) are subject to different and more restrictive working time limits under the Working Time Regulations 1998. Young workers must not work more than 8 hours per day or 40 hours per week, and these limits are absolute — there is no opt-out available. Young workers are also entitled to a rest break of 30 minutes where the working day exceeds 4.5 hours (compared to 20 minutes after 6 hours for adult workers), a daily rest period of 12 consecutive hours (compared to 11 hours for adults), and a weekly rest period of 48 consecutive hours (compared to 24 hours for adults). These enhanced protections for young workers cannot be disapplied by agreement.

Does signing the opt-out exempt the worker from rest break requirements?▾

No. The working time opt-out relates solely to the 48-hour average weekly working time limit under Regulation 4(1). It does not affect any other entitlement under the Working Time Regulations 1998. Workers who have signed an opt-out remain entitled to the daily rest period of 11 consecutive hours in every 24-hour period (Regulation 10), the weekly rest period of an uninterrupted 24 hours in each 7-day period or 48 hours in each 14-day period (Regulation 11), and the in-work rest break of 20 minutes where the working day exceeds 6 hours (Regulation 12). The employer must ensure that these rest entitlements are provided regardless of whether the worker has opted out of the weekly hours limit. In construction, compensatory rest may be provided where the nature of the work prevents rest being taken at the normal time, but the rest must still be provided.

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