From 1 December 2025, the mandatory early conciliation period before most Employment Tribunal claims in Great Britain will increase from six to twelve weeks. The change is made by the Employment Tribunals (Early Conciliation: Exemptions and Rules of Procedure) (Amendment) Regulations 2025 (S.I. 2025/1153), signed on 3 November and laid before Parliament on 4 November.
The instrument amends rule 6(1) of the Schedule to the Employment Tribunals (Early Conciliation: Exemptions and Rules of Procedure) Regulations 2014 by substituting “12” for “six”. It extends to England and Wales and Scotland. The six‑week period has applied since 8 December 2020, when S.I. 2020/1003 removed the former one‑month period and the option of a 14‑day extension.
A clear transitional rule applies. The twelve‑week window will apply only where a prospective claimant presents an early conciliation form to Acas or telephones Acas in accordance with rule 1 on or after Monday 1 December 2025. Notifications made before that date continue under the six‑week regime.
Time limits remain governed by the existing framework. Notifying Acas pauses the tribunal limitation clock while conciliation runs; where the normal time limit would otherwise expire during conciliation, claimants have at least one month from the Acas certificate to issue a claim. Moving to a twelve‑week window lengthens the maximum period that can be disregarded when calculating deadlines.
For HR and legal teams, the longer pre‑action stage creates more room to exchange information, cost assessments and settlement proposals before an ET1 is filed. Organisations should recalculate limitation dates using the Day A/Day B approach in internal templates, update staff guidance for line managers, and ensure settlement authority processes reflect the extended conciliation timetable.
Procedural requirements for lodging claims are unchanged. Claim forms must include an early conciliation number or a confirmation that no relevant proceedings are instituted or that an exemption applies; otherwise, claims risk rejection at the sift stage under the Employment Tribunal Procedure Rules 2024.
The scope of exemptions set out in the 2014 Regulations is unaffected. Exemptions include, for example, interim relief applications and certain national security‑related claims. The 2025 instrument alters only the length of the conciliation period; it does not change who must contact Acas before bringing proceedings.
Operational capacity will matter. Recent reporting has highlighted pressure on Acas, with conciliator contact sometimes occurring late in the six‑week window. A longer statutory period may ease scheduling, but outcomes will depend on available resources.
No full impact assessment accompanies the instrument; the Department for Business and Trade indicates a de minimis assessment is available on request. Employers and advisers should apply the new period to Acas notifications made on or after 1 December 2025 and keep pre‑issue strategies under review through the winter period.