Last reviewed: 5 October 2026. This guide is general information, not legal advice. It covers Great Britain (England, Wales and Scotland). Northern Ireland has its own employment law, including a different unfair dismissal qualifying period.
TL;DR
- No law requires a probation period in the UK, and no law sets its length (Acas).
- If you have one, its duration and conditions go in the written statement given on day one (Employment Rights Act 1996, s. 1(4)(ga)).
- To extend probation, confirm it in writing before the original period ends, then update the written statement within one month (Acas).
- To end employment at probation, follow a fair procedure, give the reasons in writing and the correct notice (Acas).
- From 1 January 2027, employees in Great Britain can claim unfair dismissal after six months instead of two years. The date is set by commencement regulations already made.
What a probation period is, and what the law says about it
A probation period is a time at the start of employment to check whether someone is suitable for the job. Acas puts the legal position plainly: "There's no legal requirement to have a probation period. And they can be any length of time" (Acas, what probation is).
Three points follow from the law that does exist:
- It must be in writing. Since April 2020, the written statement of employment particulars has to include "any probationary period, including any conditions and its duration" (Employment Rights Act 1996, s. 1(4)(ga)). That statement is due on the first day of employment, so the probation terms are too. Our guide to the written statement of employment particulars lists everything else it must contain.
- Day-one rights apply. Minimum wage, paid holiday, protection against discrimination, whistleblowing protection and the right to join a trade union all apply during probation (Acas).
- It is usually for employees. Acas notes that probation periods are usually for people with the legal status of employee, and that agency workers, casual workers and people on zero-hours contracts are unlikely to be employees. See UK employment contract types for the differences between statuses.
How long should probation last?
There is no statutory minimum or maximum. Acas advises tailoring the period to the job: "Probations of 6 months or less might not be appropriate for all roles", for example technical or specialist roles that need longer for training and assessment (Acas).
Acas also recommends a written probation policy covering its length, reviews, the conditions for passing, extensions and appeals (Acas, following a fair process). If the terms sit in a policy, the written statement or the contract must say so.
Unfair dismissal: two years now, six months from 1 January 2027
Today, an employee in Great Britain must normally have worked for their employer for two years before they can claim unfair dismissal at a tribunal; in Northern Ireland the qualifying period is normally one year (GOV.UK, dismissal).
Section 25 of the Employment Rights Act 2025 replaces "two years" with "six months" in that rule and removes the cap on the compensatory award. It extends to England, Wales and Scotland only. Its start date is no longer just a plan: the Employment Rights Act 2025 (Commencement No. 4 and Transitional and Saving Provisions) Regulations 2026, made on 26 May 2026, bring it into force on 1 January 2027. The new rule applies where the effective date of termination falls on or after that date, even if notice was given before it.
The government's timeline update of 25 September 2026 lists the same date, with a general warning that "All future dates remain subject to parliamentary processes and may change". Here, the date is already fixed by regulations: moving it would require amending them.
What it means in practice, according to Acas:
- someone who already has six months' service on 1 January 2027 is protected from that date;
- ending probation before the six-month mark "does not avoid legal risks", because discrimination, whistleblowing and breach of contract protections apply from day one;
- employers can still dismiss fairly after six months, provided they have a fair reason and follow a fair process.
The full calendar of the Act is in our Employment Rights Act 2025 timeline.
Extending a probation period
Acas says an employer might extend probation when performance is not yet satisfactory but likely to improve with support. The employer must (Acas, extension):
- tell the employee in writing about the extension, by letter or email;
- confirm it before the original probation period ends: failing to do so could be a breach of contract;
- update the written statement within one month, which matches the legal deadline for notifying changes in section 4 of the Employment Rights Act 1996.
Before writing, agree with the employee the length of the extension, the review points, what is expected (including training), when the final review happens and the possible outcomes. Absence is a special case: if an employee performed well before sickness or family leave, Acas says that evidence can be enough to pass them, and mishandling absence-related extensions can be discriminatory.
Template: probation extension letter
[Company name] [Date]
Dear [first name],
Extension of your probation period
Thank you for meeting me on [date of review meeting]. As we discussed, your probation period, which was due to end on [original end date], will be extended by [number] weeks and will now end on [new end date].
We are extending it because [specific, factual reason: for example, "the sales targets agreed at your three-month review have not yet been met"]. During the extension, we expect you to [objective 1, measurable] and [objective 2, measurable].
To support you, we will [training, coaching, weekly one-to-one with your manager]. We will review progress on [review date(s)] and hold a final review on [final review date]. At that review, your probation may be confirmed, or your employment may end with notice in line with your [contract / written statement].
All other terms of your employment are unchanged. This letter updates the probation details in your written statement of employment particulars.
If you have any questions, or disagree with this decision, please speak to [name] by [date].
Yours sincerely, [Name, job title]
Why each part matters:
- The original end date shows the extension was confirmed in time: send the letter before that date.
- Specific reasons and objectives can be measured at the final review; vague concerns cannot.
- Support and review dates are what Acas expects a fair extension to include.
- "This letter updates…" covers the one-month deadline for changes to the written statement.
Ending employment at the end of probation
Acas treats dismissal during probation as a last resort, after performance support or an extension. When an employer dismisses, it should follow a fair procedure and give the reasons in writing, and it must give the correct notice: the minimum statutory period or the contractual one (Acas, dismissal).
The statutory minimum is set by section 86 of the Employment Rights Act 1996: one week once the employee has been continuously employed for one month or more, then one week per full year of service from two years, up to twelve weeks. A contract can promise more, never less. When someone passes probation, Acas recommends confirming it in writing and giving them any new terms, such as a longer notice period or new benefits (Acas).
Template: letter ending employment after probation
[Company name] [Date]
Dear [first name],
Outcome of your probation period
Thank you for attending the probation review meeting on [date], where you were accompanied by [name, if applicable].
I am writing to confirm that you have not successfully completed your probation period, and that your employment will end. The reasons are:
- [reason 1, factual, linked to an objective set at the start or at the extension];
- [reason 2].
These points were discussed with you at your reviews on [dates], and we provided [support given].
You are entitled to [length] notice under your [contract / written statement]. Your last day of employment will be [date]. [Choose: You will work your notice. / You will not be required to work your notice and will be paid for it, as your contract allows.]
Your final pay will include your salary up to your last day and any holiday you have accrued but not taken. Please return [laptop, badge, documents] by [date].
If you wish to appeal this decision, please write to [name] within [number] working days, explaining your reasons.
Yours sincerely, [Name, job title]
Why each part matters:
- The meeting and the reviews show a process was followed.
- Written reasons are what Acas recommends, and a check that the decision has nothing to do with a protected characteristic or whistleblowing.
- The notice clause must match the contract and never fall below the statutory week. Only pay in lieu of notice if the contract allows it, or take advice.
- An appeal route is part of the probation policy Acas describes.
What this means for recruitment agencies
- Perm placements. Rebates are commercial terms, not legal ones. With unfair dismissal protection after six months from January 2027, expect clients to look harder at the first months of a hire. Our recruitment terms of business template shows how to write a rebate clause.
- Your own team. From 1 January 2027, any employee with six months' service is protected, including those already in post: plan probation reviews with that threshold in mind.
- Contractors. Agency workers and limited company contractors are rarely on probation. Their rights depend on their status, covered in agency workers in the UK.
Where Marvin fits
Marvin is a recruitment CRM and ATS. Desk keeps each perm placement with the candidate, the client and the start date; Cash drafts the placement fee invoice, and credit notes handle a rebate. For contract desks, People holds each assignment with its day rates, and clients sign day and half-day timesheets from a secure link without an account. See contract and temp recruitment software.
Marvin does not write probation letters, manage your clients' HR processes or run PAYE payroll. The templates above are a starting point for your own documents and your advisers.
Want to see how a placement flows from shortlist to invoice? Book a demo.
Frequently asked questions
Is a probation period a legal requirement in the UK?
No. Acas states that there is no legal requirement to have a probation period and that it can be any length. If you use one, its duration and conditions must appear in the written statement of employment particulars given on the first day of employment.
How do you extend a probation period?
Tell the employee in writing, by letter or email, before the original probation period ends; Acas warns that failing to do so could be a breach of contract. Agree the length of the extension, the review points and what is expected, then update the written statement within one month.
Can an employee claim unfair dismissal during probation?
In Great Britain, an employee normally needs two years of service to claim ordinary unfair dismissal. For dismissals with an effective date of termination on or after 1 January 2027, the qualifying period drops to six months under the Employment Rights Act 2025. Protection against discrimination, against detriment for whistleblowing and for breach of contract applies from day one, probation included.
How much notice do you give when someone fails probation?
At least the notice set out in the contract or written statement, and never less than the statutory minimum: one week once the employee has worked continuously for one month or more. Probation clauses often set a shorter contractual notice, but they cannot go below that statutory floor.
Does the Employment Rights Act 2025 change probation periods?
Not directly. Acas notes that the Act does not affect probation periods: there is still no legal requirement to have one, and they can be any length. What changes is the unfair dismissal qualifying period, which falls to six months from 1 January 2027 in Great Britain.
