Time limit for unfair dismissal — Can one day out sink your claim (EDT guide with Gisda)

William Slivinsky
Sep 16
5 min read

Can one day out sink your claim? In terms of time limit for unfair dismissal, the key question is whether you calculated EDT correctly. This is a starting point. We then need to consider the proper application of section 207B ERA 1996, known as ACAS stop the clock. In this article, I want to show you that employers will often argue the time limit, even if there is a one-day difference.

If you do not known how tribunals actually fix the “effective date of termination” (EDT) — and why s.97 ERA 1996 isn’t enough on its own, go to Time Limits for Unfair Dismissal | When EDT time starts and how to extend it ?

Every unfair dismissal timeline begins with one question: "What is correct EDT" Employers will often argue your ET1 was late, even by one day. In the textbook employment tribunal case below, that single day decided jurisdiction and allowed the claimant's case to proceed. This is what I want you to protect in your case. Understending how EDT is fixed arm you with good defence of your claim.

Time limit for unfair dismissal - The 60-Second Story (Textbook “One Day” Case)

The employee handed in a resignation on Sunday, but the letter was dated Monday and said “with immediate effect.” Managers didn’t work Sundays; an admin (Mon–Fri) happened to read an email on Sunday but formally replied Monday, confirming Monday as the final date. The employer argued the EDT was on Sunday and had good reason, because if the tribunal was persuaded the case would be out of time and the employee would need to prove "not reasonably practicable".

Full judgment can be found here [2012] UKEAT 0039_11_1704 (17 April 2012)

The tribunal (upheld on appeal) fixed the EDT = Monday — which made the claim in time. If Sunday had been the EDT, the claim would have been one day late.

📅 Mini timeline

• Sun 21 Nov — Letter delivered (dated Mon)

• Mon 22 Nov — Employer accepts; final date confirmed

• Mon 21 Feb — ET1 presented → in time

Why s.97 ERA 1996 Isn’t Enough (by itself)

Section 97 says EDT is the day termination “takes effect.” But what does “takes effect” mean in real life? That’s where case law — and practical reality — fill the gap: who actually reads the communication, when, and what date the employee clearly fixed.

In this case it was an employee handing resignation letter on Sunday when HR was closed. She put on ther termination with immediate effect from Monday. This scenarion suite the circumstance as if an employee was given an unfair dismissal letter with effective date on following day

➡︎ For the step-by-step rules and how to pause/extend time, see: Time Limits for Unfair Dismissal: When EDT starts — and how to extend it ?

⚖️ The Heart of the Law: Gisda Cyf v Barratt

The Supreme Court called EDT a term of art that anchors multiple rights, including the start of the unfair dismissal time limit: “The effective date of termination of employment is a term of art that has been used in successive enactments to signify the date on which an employee is to be taken as having been dismissed. The fixing of the date of termination is important for a number of purposes. These include, but are by no means confined to, the marking of the start of the period within which proceedings for unfair dismissal may be taken.” — Gisda Cyf v Barratt [2010] ICR 1475, per Lord Kerr."

EDT isn’t a mere admin date. It’s the operative legal date that starts the three months minus one day clock. Courts apply fairness and real-world communication when deciding it. If an employee was sent a dismissal letter on 1 August, but due to a holiday only opened it and read it on 15 August, the EDT is 15 August, not the 1st.

How Judges Fix the EDT (Practical Principles)

• Clarity of the message — If a resignation says “with immediate effect” from the date on the letter, that date matters.

• Real-world reading — Weekends, out-of-office patterns, and who actually reads dismissals/resignations count.

• What actually happened > labels — P45/payroll dates do not set EDT.

• Objective lens — The question is what a tribunal concludes actually happened, not what parties later “agree” it was.

In this case the judge decised that the EDT fell on Monday because the employee’s resignation letter expressly took effect from the date printed on it —Monday— “with immediate effect,” and, viewed objectively, she had no reasonable basis to think the employer would read or act on it on Sunday (the the HR did not work Sundays and the admin recipient was a Monday–Friday worker). Although the email text with resignation was seen on Sunday night by the office, the formal acknowledgement came on Monday, aligning with the employee’s stated date. Applying the fairness-and-reality approach from Gisda Cyf v Barratt —that time should not run before the other side can reasonably know, and not earlier than the clear operative date communicated—the tribunal fixed the EDT at Monday 22 November, not Sunday 21 November.

⚠️ Why The One Day Mattered (Jurisdiction Math)

In this instance, as is often the case, the employer contended that the EDT was on Sunday, because the deadline is three months minus one day. If the judge accepted this argument, the claimant would be one day late. What we learn from this case is that it's not uncommon—in fact, I've seen many instances where the employer was extremely late with its 28-day deadline for a response, defended the lateness and then quickly argued that the the employee was late too. The key difference is that a late employee faces a much stricter "not reasonably practicable" test to overcome, compared to employers who are assessed against the multi-layered Swain test (from Kwik Save v Swain) which in substancial claims value is quite difficult to fail.

✅ Perfect Your EDT (constructive unfail dismissal)

• Date your resigantion letter for the exact day you intend it to bite (especially if saying “immediate”).

• Record working patterns of the person who would read it (rotas).

• Keep the employer’s acknowledgement confirming the operative date.

• Don’t rely on payroll/P45 to calculate EDT and start the clock.

• Count precisely: Three months minus one day from EDT but never claim last minute.

• Know your lifelines: Start Acas Early Conciliation early to pause the clock.

Common Traps We See

• Weekend resignations/dismissals assumed to bite the same day.• Back-dated letters trumping what actually happened.• Confusing notice periods with the EDT for limitation purposes.• Leaving filing until the very last day with no EC buffer.

Key Takeaway

EDT follows reality and fairness, not admin artifacts, e.g., P45. Fix the right date first, evidence who could read it when, and keep any acceptance that confirms it. One day can decide the tribunal’s jurisdiction. In extreme cases, when you are late by the date on your resignation letter, try to find confirmation of the receipt. The date will be a big obstacle for you to prove later EDT, but at least you will have room to argue. You will always be better off arguing the EDT date than proving not reasonably practicable.

Next step:➡︎ Time Limits for Unfair Dismissal: When EDT starts — and how to extend it https://www.unfairdismissal.org/post/time-limits-for-unfair-dismissal-when-edt-time-starts-and-how-to-extend-it