Take two employees who are underpaid on consecutive days, one on 30 September 2026 and the other on 1 October. The first has until 11:59pm on 29 December 2026 to start a tribunal claim over the missing money. The second has until 11:59pm on 31 March 2027, roughly three months longer for what is otherwise the same wrong. Both dates come from Acas's own guidance. The gap between them is the whole story of a change that took effect on 1 October: for most employment tribunal claims in England, Wales and Scotland, the time limit is now six months minus one day instead of three months minus one day.
The Employment Rights Act 2025 did the heavy lifting, covering claims for unfair dismissal, discrimination and unlawful deductions from wages, among others. Breach of contract claims were left out of the Act itself, so the government extended those through separate regulations; in England and Wales they moved on 1 October as well, while in Scotland they switch on 9 November 2026 and stay at three months until then. A handful of claims already had six months before the reform, namely statutory redundancy pay, equal pay, certain claims against a trade union and certain armed forces claims, and the change brings the majority into line with them. Northern Ireland runs its own industrial tribunals, and according to the government's business.gov.uk guidance the change reaches only a few claims there, such as those under the National Minimum Wage Act 1998. The stated aim is to give employees and employers more time to settle things internally or through conciliation, and to weigh up whether a claim is worth bringing at all. Personnel Today reports that some employment lawyers expect the opposite effect, with longer uncertainty and more pressure on a tribunal backlog that is already heavy. Which of those turns out to be right will not be clear for months, but the new arithmetic applies to you from day one.
The date that decides which clock you are on
The new limit is not retrospective. Where the act complained of falls on or after 1 October 2026, the claimant has six months; where it happened wholly before that date, the old three-month limit still applies, as Browne Jacobson sets out in its guide for employers. In most cases the "act" is the thing that went wrong: the underpayment, the dismissal, the discriminatory remark, or the last in a series of them. Acas says an unfair dismissal clock generally starts on the last day of your notice period, or on the day you were dismissed if no notice was given, while a pay claim runs from the date you were not paid correctly and a discrimination claim from the most recent incident you include.
| What happened | Date | Last day to start the claim |
|---|---|---|
| Dismissed without notice (old rules) | 15 September 2026 | 14 December 2026 |
| Underpaid (old rules, Acas example) | 30 September 2026 | 29 December 2026 |
| Underpaid (new rules, Acas example) | 1 October 2026 | 31 March 2027 |
| Dismissed without notice (new rules, Lewis Silkin example) | 15 October 2026 | 14 April 2027 |
Every row follows the same sum: add three or six calendar months depending on the rules in force, then take off one day, with the deadline falling at 11:59pm on the last day. None of them allows for early conciliation, which can push the real date later, and all of them assume a single clean event.
Real disputes are rarely that tidy. Lewis Silkin warns that where a claimant argues discrimination was an ongoing course of conduct, the six-month limit can run from the end of that period, which draws in incidents from before 1 October. Someone whose notice period straddles the changeover should not assume which side of the line they sit on, because the commencement regulations set a "relevant date" for each type of claim and time limits are strictly enforced in most cases. If you are in any doubt, work to the earlier deadline and ask the Acas helpline or an adviser to confirm the later one.
Early conciliation stops the clock, if you start it in time
In most cases you cannot go straight to a tribunal. Acas says you must notify it if you want to make a claim, and GOV.UK says you will usually need an early conciliation certificate for each respondent before you can file. Notifying Acas pauses your time limit until conciliation ends, but Acas is explicit that this only works if you notify within the original limit, so a notification sent one day late pauses nothing. Since 1 December 2025 conciliation can run for up to 12 weeks, double the previous six, and the explanatory memorandum to those regulations says the maximum will be reviewed in October 2026; Lewis Silkin does not expect it to shrink given the pressure on Acas. Once the certificate is issued, the employee in a case like the one below gets a further month to lodge the claim. Put the pieces together and Lewis Silkin's worked example has someone dismissed on 15 October 2026, notifying Acas on 13 April 2027, receiving the certificate on 5 July and filing by 5 August 2027, almost ten months after the dismissal.
There is no fee to make a claim, GOV.UK confirms, although a tribunal can order you to pay the other side's costs if it decides you acted unreasonably. Early conciliation itself is voluntary for both parties, and the conciliator cannot give legal advice, tell you whether your case is strong or help you prepare it. What it can do is put a settlement conversation on the table with a third party in the room.
A longer deadline is not a reason to wait
Does a six-month window mean you can take your time deciding? No, and the first reason is the one that catches people out: a grievance, a disciplinary process or an appeal does not pause the clock. Acas says plainly that if those procedures drag on, you still have to notify it before your limit runs out. Say a grievance takes eight weeks to hear and the appeal another six; that is more than half of your six months gone, and for a dismissal you are counting from the day employment ended, not the day the appeal was refused. The second reason is evidence, because emails get archived, colleagues move on and memories of who said what in a meeting fade faster than anyone expects. Lewis Silkin and Browne Jacobson both make this point to employers about their witnesses, and it applies to you in exactly the same way. A judge can accept a late claim, and Acas confirms as much, but it also says limits are strictly enforced in most cases, which makes discretion a poor plan.
The better approach is dull and works:
- Your deadline, calculated and in the calendar on day one, with a reminder at the three-month mark.
- Keep your contract, payslips, any dismissal or outcome letters and the messages about the dispute, and note the dates of key conversations while you still remember them, among other records.
- Acas says a judge will usually expect to see that you tried to resolve things with your employer first, and that failing to do so could affect your compensation, so raise the problem in writing.
- Notify Acas when you think you might claim rather than when you are certain.
One exception runs the other way. For some unfair dismissals, such as certain whistleblowing and trade union cases, you can apply for interim relief, which Acas says can help prevent financial difficulty, and the deadline there is seven days rather than six months. You may not need to notify Acas first.
What employers and managers should change this month
If you run a team or a small business, the first job is dull: business.gov.uk tells employers to update policy documents and handbooks that still say three months. The second job matters more. Browne Jacobson points out that many employers' retention policies delete HR documents about three months after someone leaves, which matched the old limit and now leaves a six-month window, plus conciliation, with nothing behind it. Its estimate is that the whole process can stretch to nine or ten months before a claim is even filed, with a final hearing possibly three or more years after the events because of the tribunal backlog. Lewis Silkin adds that witnesses leave, so take current contact details, consider a clause in contracts requiring reasonable help with legal proceedings after employment ends, and take a written statement before a key person walks out of the door. Deleting leaver files at three months is now a mistake. Choose a longer period you can justify under data protection rules, write the reason down, and apply it before the first leavers under the new regime reach the old three-month mark on 1 January 2027.
Waiting is also part of the cost. An employer who dismisses someone in October may not hear about a claim for the best part of a year, once the filing window and the tribunal backlog are added together. Managers who record decisions as they make them, in plain language, will find that paper trail far easier to rely on than recollection.
What arrives next
This is the first of several dates in a busy autumn and winter. On 30 October, the employer duty on sexual harassment tightens from "reasonable steps" to "all reasonable steps", and employers become liable for certain harassment of staff by third parties such as clients and customers, per Personnel Today's summary of the government timetable. On 1 January 2027 the qualifying period for unfair dismissal falls to six months for dismissals from that date, and compensatory awards are uncapped. GOV.UK is careful to say that future dates in its timeline update remain subject to parliamentary processes and may change.
Check any deadline you work out, including the ones in the table above, against Acas's time limits page, which was updated on 1 October, before you rely on it. Treat all of it as general information rather than legal advice, because the cost of a miscalculation can be a claim that never gets heard.