Tribunal Time Limit: 6 Months from 1 Oct 2026 (Acas Explained)

The 6-month tribunal time limit reform from 1 October 2026

Historically, employment tribunals in England, Wales, and Scotland operated under a strict three-month limitation period (less one day). This short window forced claimants to rush into litigation, overwhelmed early conciliation officers, and caused many valid claims to be struck out on technical timing grounds.

Under section 152 and Schedule 12 of the Employment Rights Act 2025 (commenced by SI 2026/954), the statutory time limit for the vast majority of employment tribunal claims increases from three months to six months less one day.

Crucially, this reform applies to claims where the 'relevant date' falls on or after 1 October 2026. The amendment is strictly non-retrospective: if your dismissal, discrimination incident, or breach of contract occurred on or before 30 September 2026, the legacy three-month limitation period continues to govern your claim.

Direct answer: For events on or after 1 October 2026, you have six months less one day from the relevant date to contact Acas or bring a tribunal claim. Acas Early Conciliation pauses this clock, and you always get at least one calendar month after your Acas certificate is issued. Calculate your exact filing deadline with our free Tribunal Deadline Calculator.

Identifying your relevant date by claim type

The six-month countdown does not begin on an arbitrary date; it runs strictly from the statutory 'relevant date' defined by the cause of action:

1. Unfair Dismissal & Constructive Dismissal: The relevant date is the Effective Date of Termination (EDT) under ERA 1996 s.97 — the date notice expires, or the date summary dismissal takes effect.

2. Equality Act 2010 Discrimination & Harassment: The relevant date is the date of the discriminatory act. If there is a continuing state of affairs or continuing series of acts, the clock runs from the date of the last act in the series.

3. Breach of Contract & Wrongful Dismissal: The relevant date is the date of the breach, which in employment tribunals is almost always the date employment terminates.

4. Unlawful Deductions from Wages: Under ERA 1996 s.23, the clock runs from the date the deducted payment was made (or the date of the last deduction in a series).

The 'less one day' calculation rule and month-end calendar traps

In UK tribunal law, time limits run for calendar months 'less one day' from the corresponding date of the relevant event. Under the ruling in *Dodds v Walker*, adding months brings you to the corresponding numerical date in the target month; the limitation rule then deducts one calendar day.

For example, if your dismissal takes effect on 1 October 2026, adding six calendar months brings you to 1 April 2027. Deducting one day establishes your primary tribunal deadline as 31 March 2027.

Month-end ambiguity warning: When the relevant date falls on the final day of a month (such as 31 August), adding six months to February causes a calendar clamp because February has fewer days. Tribunals take a strict approach to corresponding date arithmetic. To protect your claim, always treat the earlier date as your deadline.

Acas Early Conciliation arithmetic: Day A and Day B explained

Before any claimant can submit an ET1 claim form to an employment tribunal, they are legally required under section 18A of the Employment Tribunals Act 1996 to notify the Advisory, Conciliation and Arbitration Service (Acas). Early conciliation stops the limitation clock.

Under section 207B of the Employment Rights Act 1996, limitation calculations use two critical benchmark dates:

• Day A: The day on which Acas receives the claimant's completed early conciliation notification form.

• Day B: The day on which the claimant receives (or is deemed to receive) the Acas Early Conciliation Certificate confirming conciliation has ended.

The Pause Calculation: Under s.207B(3), the period beginning on the day after Day A and ending on Day B does not count towards the limitation period. In calendar arithmetic, the number of days added to your primary deadline is exactly Day B minus Day A in whole calendar days.

The one-month statutory backstop: Luton Borough Council v Haque

What happens if conciliation ends very close to or after the primary deadline? Section 207B(4) introduces a vital safety net known as the one-month backstop:

If the limitation period (as extended by the Day A to Day B pause) would expire between Day A and one calendar month after Day B, the deadline is automatically extended to one month after Day B.

In the landmark Employment Appeal Tribunal decision *Luton Borough Council v Haque* [2018] ICR 1388, the court clarified that this test is applied to the already-extended primary date, not the original date. This ensures that a claimant who engages in conciliation right up to their deadline is guaranteed at least one full calendar month after the certificate is issued to draft and lodge their ET1 form.

Luton BC v Haque Worked Example: Primary deadline is 19 September 2026. Claimant contacts Acas on 22 July (Day A) and certificate issues on 22 August (Day B). Conciliation lasted 31 days. Extended primary deadline = 19 September + 31 days = 20 October. The one-month backstop from Day B is 22 September. Because the extended deadline (20 Oct) is later than the backstop (22 Sep), the final deadline is 20 October 2016.

Five costly tribunal deadline mistakes to avoid

Tribunals strictly enforce time limits. If you file even one day late, the tribunal will only accept your claim under extremely narrow discretionary grounds (such as 'not reasonably practicable' for unfair dismissal or 'just and equitable' for discrimination). Avoid these five common pitfalls:

• 1. Contacting Acas after the primary deadline has expired: Acas early conciliation cannot revive a dead claim. If Day A is even one day past your primary deadline, no statutory extension is granted.
• 2. Believing that internal workplace appeals stop the tribunal clock: Lodging an appeal with your employer does NOT pause or extend statutory tribunal deadlines. You must initiate Acas conciliation regardless of pending internal appeals.
• 3. Counting weeks instead of calendar months: Six months is not 26 weeks, nor is it 180 days. Adding calendar months less one day produces a different date.
• 4. Assuming Day B is when Acas emails or posts: Deemed receipt rules apply. For certificates sent by email, receipt is generally deemed on the date of transmission. For posted certificates, deemed delivery rules under the CPR apply.
• 5. Overlooking regional Scottish jurisdictional rules: In Scotland, contractual tribunal claims were commenced under separate Scottish statutory instruments (SI 2026/759). Ensure regional dates are verified.

Step-by-step worked timeline examples

Here are three standard timeline calculations illustrating the new six-month regime:

Example 1 — Standard dismissal under 2026 rules (no Acas): EDT is 1 October 2026. Because EDT is on or after 1 October 2026, the six-month rule applies. Primary deadline = 1 October 2026 + 6 calendar months (1 April 2027) less 1 day = 31 March 2027.

Example 2 — Dismissal with Acas conciliation: EDT is 2 November 2026. Primary deadline is 1 May 2027. Claimant submits Acas form on 10 November 2026 (Day A) and certificate issues on 20 November 2026 (Day B). Pause duration is 10 days. Extended deadline = 1 May 2027 + 10 days = 11 May 2027. Backstop is 20 December 2026. Because 11 May 2027 is beyond the backstop, final deadline is 11 May 2027.

Example 3 — Late conciliation triggering the backstop: EDT is 1 October 2026. Primary deadline is 31 March 2027. Claimant contacts Acas on 25 March 2027 (Day A) and certificate issues on 30 March 2027 (Day B). Pause is 5 days (extended date 5 April 2027). The one-month backstop from Day B is 30 April 2027. Because 5 April falls before 30 April, section 207B(4) extends the final deadline to 30 April 2027.

Statutory citations and how to protect your claim

All calculations cited in this guide reflect primary UK legislation as reviewed on 11 October 2026:

• Employment Rights Act 2025 (c. 36), s. 152 and Schedule 12: extended the standard limitation period from 3 months to 6 months less one day.

• Employment Rights Act 1996, section 207B: governs the extension of time limits to facilitate early conciliation.

• Luton Borough Council v Haque [2018] ICR 1388 (EAT): established the authoritative interpretation of section 207B(4) backstop arithmetic.

• The Employment Tribunals (Extension of Jurisdiction) Orders 2026 (SI 2026/758 England & Wales; SI 2026/759 Scotland).

To model your own timeline and export automated calendar alerts (.ics), use our free UK Tribunal Deadline & Qualifying Calculator. For questions regarding qualifying service lengths, read our companion guide Unfair Dismissal After 6 Months (1 Jan 2027): What Changes.