Work to rule or refuse overtime: can they dock a whole shift?

You work seven hours of an eight-hour shift but refuse one contractual task as part of a union dispute. Can the boss withhold all eight hours’ pay? In Great Britain, sometimes yes. But refusing genuinely voluntary overtime is different. An employer cannot turn an optional extra into a duty just by threatening your wages.

What to do before your next shift

1. Save the paperwork. Keep your contract, job description, overtime offers, rotas and payslips. Highlight the duty you plan to refuse. “We always do it” does not settle whether it is compulsory.
2. Ask your rep what the union has called. Check that the ballot authorised action short of a strike and that your job and workplace are covered. Ask for the action dates and the employer’s pay response.
3. Get the pay position in writing. Ask: “Are you rejecting partial performance? Which contractual duty do you say we are refusing, what pay will you withhold, and for which dates?” A rejection warning can put pay for work you actually do at risk.
4. Plan for the missing pay. Ask your union about hardship support and legal help before the deduction lands. Eligibility for support varies. Do not assume joining now covers an existing dispute.
5. Challenge a deduction promptly. Record what you did each shift and what managers instructed you to do. Send the payslip and warning to your rep. If you have no rep, contact Acas, Citizens Advice or a law centre. Do not wait for a grievance to finish before checking a legal deadline.

This guide states the Great Britain position as at 1 October 2026, including the tribunal time-limit changes taking effect that day. Northern Ireland has separate rules, explained below.

What that ballot question actually means

If your ballot asks whether you are prepared to take part in “industrial action short of a strike”, it is asking whether you support withdrawing some labour while continuing to work. Under section 229 of the Trade Union and Labour Relations (Consolidation) Act 1992, the strike and action-short-of-a-strike questions are separate:

Are you prepared to take part in a strike? Are you prepared to take part in industrial action short of a strike?

A yes vote for a strike does not also authorise an overtime ban. A yes vote for action short of a strike does not authorise a walkout. The union decides what action to call within its mandate. Voting yes does not itself instruct you to refuse every extra task.

Acas confirms that at least 50% of eligible members must vote, with more votes for the action than against. The planned repeal of the turnout threshold is not yet in force. Voting need not be postal. Electronic and in-person ballots are also permitted.

For ballots opened on or after 18 February 2026, the mandate lasts 12 months from the ballot’s closing date and the additional 40% support threshold for important public services no longer applies. Earlier ballots retain the old rules. Notices of action received by employers on or after 18 February require at least 10 days’ notice. The government’s transition guidance explains those dividing dates. Our strike ballot guide covers the process.

Work to rule, overtime ban, go-slow: what counts

The label does not decide your pay. What matters is whether you are refusing something your contract requires.

A supermarket worker declining an optional Sunday shift is in a different position from a warehouse picker deliberately slowing down during paid hours. So is a care-home porter refusing a task covered by a reasonable-duties clause. The written job title alone will not answer the question.

Check your overtime wording now. For the three contract types see overtime pay: UK rules, rates and calculations.

Can they dock a whole shift for partial work?

Yes, where you refuse contractual work and the employer clearly rejects partial performance. It says, in effect, that it requires the full job and will not pay for a substitute. If you continue doing only part, the work you do may be treated as voluntary and unpaid.

The leading cases are Miles v Wakefield Metropolitan District Council [1987] AC 539 and Wiluszynski v Tower Hamlets [1989] ICR 493. In Miles, a registrar refused to conduct Saturday weddings but did other work during that time. The council could withhold pay for the Saturday hours after rejecting that arrangement. It did not acquire a right to withhold the pay he had earned on other days.

Wiluszynski shows the wider risk. An employee who refused public enquiries throughout a dispute lost pay for the period despite doing other duties. David Mead’s analysis of the cases explains why the period affected by the refusal matters. A continuing refusal of a contractual duty can put more than one shift at risk.

If the employer accepts partial performance, it cannot justify withholding everything simply by claiming it rejected that work. It may still have a basis for a smaller deduction. The contract, work withheld and legal basis for the deduction need checking. There is no universal rule that one refused hour always permits exactly one hour’s deduction.

Salaried workers should also check the divisor payroll uses. In Hartley v King Edward VI College [2017] UKSC 39, the Supreme Court held that the teachers’ annual salaries should be divided by 365 for a strike day, not 260. On £26,700 that would be £73.15. The decision depends on the contract. It is not a formula to apply blindly to every salary or partial shift.

Do you have to work the overtime at all?

Only if your contract makes it compulsory. Three types matter:

1. Guaranteed overtime. The employer must offer it and you must work it, subject to the contract and applicable legal limits.
2. Non-guaranteed compulsory overtime. The employer need not offer it, but you must work it when it is properly required under the contract.
3. Voluntary overtime. You can decline it without breaching an obligation to work those hours.

Read the actual wording and any collective agreement. “Reasonable overtime when required” needs advice about what is reasonable in your circumstances. Working-time and safety rules still apply. Regularly volunteering does not, by itself, settle whether future overtime has become compulsory.

There is a separate question for industrial-action law. A collective refusal of voluntary overtime can still be industrial action even though the refusal is not a contractual breach. Power Packing Casemakers Ltd v Faust [1983] QB 471 illustrates that distinction. Do not assume “voluntary” means you can ignore the union’s ballot and notice requirements.

Can you be sacked or punished for it?

If you are an employee, dismissal whose main reason is your participation in protected industrial action is automatically unfair under section 238A. No qualifying service is needed. For action you began on or after 18 February 2026, there is no longer a 12-week cap on that protection.

Action you began before that date remains under the older rules, with broad automatic protection during the first 12 weeks and more limited protection afterwards. The dividing date is when you began the action, not simply when the union first balloted.

Protected action means more than a union calling it official. It must meet the statutory requirements, including the ballot and notice rules, and relate to a qualifying trade dispute under section 219. Non-members in the bargaining unit can join protected action too. Ask the union whether you are covered.

Unofficial action is much riskier. Section 237 generally bars unfair dismissal claims where you were taking unofficial industrial action at dismissal, subject to limited statutory exceptions. Union authorisation and legal protection are different questions. Get advice rather than relying on a colleague’s assurance that an unballoted ban is safe.

Rota cuts, blocked training or withdrawn overtime opportunities can raise different issues from a deduction for the action itself. As at 1 October, the gap exposed by Mercer [2024] UKSC 12 has not been closed by operative detriment regulations. Separate protection for union membership and activities may help on the particular facts, but cannot simply be assumed to cover industrial action.

Zero-hours and agency labels do not settle your legal status. If you are not an employee, you cannot bring an unfair dismissal claim. The proposed detriment protection is framed for workers more widely. Genuinely self-employed people cannot assume these employment protections apply. If shifts disappear, save the rota history and messages and seek advice now. Waiting for a future law will not necessarily protect an earlier incident.

How to challenge docked pay

Start with the amount, dates and explanation. Write to payroll and your manager stating which contractual work you performed and why you dispute the deduction. Ask your union to challenge a common deduction collectively. Keep your own evidence even if the union is dealing with it.

The usual unlawful deduction from wages claim has a specific trap here. Section 14(5) of the Employment Rights Act 1996 excludes deductions made on account of taking part in a strike or other industrial action from section 13 protection. That does not make any amount lawful. It means the ordinary wages-claim route is generally unavailable for those deductions.

A claim for money due under the contract may be the route instead. Do not assume that means an employment tribunal while you remain in the job. In England and Wales, the tribunal’s contract jurisdiction requires an employee’s claim to arise or remain outstanding when employment ends. Someone still employed will generally need to consider a civil court claim. Scotland uses the sheriff court rather than the county court. A worker who is not an employee also needs advice about the correct forum. Do not resign just to gain a tribunal route.

Check the deadline for the claim you actually have

Acas’s time-limit guidance says most tribunal claims concerning problems on or after 1 October 2026 have six months less one day, while most problems before that date keep three months less one day. Scotland’s tribunal contract-claim extension is scheduled for 9 November 2026. These are tribunal rules, not a six-month deadline for every court claim.

Ask an adviser to identify the claim, its trigger date and the right deadline. A tribunal contract claim’s time limit is linked to termination, not simply the payday. For tribunal claims requiring early conciliation, notify Acas in time. Timely notification pauses the clock; a grievance does not. Our tribunal deadlines guide explains the process.

Get help from your existing union or Acas. Usdaw organises retail workers, UNISON and GMB organise in care and NHS support, and Unite organises in logistics. Check which union represents your workplace through our union finder guide. Citizens Advice and law centres can help you find advice on the court route. Joining a union is useful; automatic legal cover for a dispute already under way is not promised.

What is different in Northern Ireland?

The Great Britain reforms above do not apply. Nidirect’s industrial-action guidance describes a separate regime with postal ballots, seven days’ notice of action and no Great Britain-style 50% turnout threshold. Action normally needs to begin within four weeks of the ballot, extended to eight by agreement.

The older dismissal rules also remain, with broad protection for the first 12 weeks and more limited protection after that. Use the Labour Relations Agency rather than Acas for conciliation and advice. Do not import the Great Britain tribunal deadline or proposed detriment right into a Northern Ireland dispute. See our Northern Ireland employment-law guide.

Questions people ask

Is refusing overtime the same as going on strike?

An overtime ban is action short of a strike for ballot purposes. It can be industrial action even when the hours are genuinely voluntary. Contractual breach is a separate question. Voluntary hours you decline are unpaid, but refusing them should not reduce pay for contractual work you perform in full.

Does a yes vote mean we have to refuse every extra task?

No. The ballot authorises the union to call the relevant form of action. Follow the union’s actual instructions and check the dates, workplaces and duties covered. Do not invent your own version of the ban.

Does being allowed to work prove the employer accepted partial performance?

No. An employer may make clear that it rejects partial performance without physically stopping you working. Its warning, subsequent instructions and conduct all matter. Save them. The fact it benefited from some work does not settle the pay dispute.

Can a rejection warning take away pay for earlier, fully worked shifts?

Not simply because you later refuse a task. The employer needs a legal basis for the period it withholds. Ask it to identify the contractual obligation and dates. A continuing refusal across several days is different from a refusal confined to one shift.

What if shifts disappear after the overtime ban?

Keep the old and new rotas, offers and messages. Losing future work may raise retaliation or contractual issues rather than a deduction from wages already earned. Your employment status matters. Get advice now about the rights in force when the treatment happened, not those proposed for a later date.

Can we claim through the tribunal while still employed?

Do not assume so. The industrial-action exception generally blocks the usual unlawful-deduction claim. A tribunal contract claim requires employment to have ended and other conditions to be met. Ask your union or adviser whether the civil court route is needed instead.

Sources

1. Trade Union and Labour Relations (Consolidation) Act 1992, section 229, ballot questions, legislation.gov.uk.
2. Section 219, protection from tort liability, legislation.gov.uk.
3. Section 237, unofficial industrial action, legislation.gov.uk.
4. Section 238A, dismissal for protected industrial action, legislation.gov.uk.
5. Trade union law: transition to Employment Rights Act 2025, GOV.UK.
6. The law on industrial action, Acas, updated 25 August 2026.
7. Section 236A, detriment for industrial action, legislation.gov.uk.
8. Draft Protection Against Detriment (Industrial Action) Regulations 2026, legislation.gov.uk. Draft, not an operative right at the review date.
9. Hartley v King Edward VI College [2017] UKSC 39, Supreme Court, especially paragraphs 25, 33 and 41.
10. We’re Miles Apart: Disproportionate Deductions from Wages, Industrial Action, and Human Rights, David Mead, Industrial Law Journal, 2023. Analysis of Miles, Wiluszynski and the distinction between accepting and rejecting partial performance.
11. Industrial action: performance and pay, Devereux Chambers, 2015. Commentary on Power Packing Casemakers Ltd v Faust. Not relied on for current ballot rules.
12. Written evidence concerning the 2023 marking and assessment boycott, House of Commons Education Committee. Source for the reality-check account of 100% deductions.
13. Employment Rights Act 1996, section 14(5), industrial-action deductions, legislation.gov.uk.
14. Employment Tribunals Extension of Jurisdiction (England and Wales) Order 1994, article 3, legislation.gov.uk.
15. England and Wales Order, article 7, tribunal contract-claim time limits, legislation.gov.uk. Read with the 2026 amendments and Acas’s current time-limit guidance.
16. Employment Tribunals Extension of Jurisdiction (Scotland) Order 1994, article 3, legislation.gov.uk.
17. Employment tribunal time limits, Acas, updated 1 October 2026.
18. Industrial action, nidirect.
19. National Minimum Wage and National Living Wage rates, GOV.UK.