Section 13 notice served on the wrong form: what to do next

The short answer

If your Section 13 notice was served on the wrong form, or with a mistake in the dates, it may not be valid. You cannot correct a served notice by letter. The safe fix is to serve a fresh, correct Form 4A as soon as possible. The new rent then starts on the first valid date counted from the new notice, so every week of delay pushes the increase back.

This guide explains what can go wrong when a Section 13 notice is served on the wrong form or with errors, when to re-serve, and how much time the mistake costs, with a worked example. It is general information for landlords in England, not legal advice.

Why the form and dates matter

Section 13(2) of the Housing Act 1988 lets a landlord propose a new rent by serving a notice “in the prescribed form”. For a private assured tenancy in England, that has been Form 4A since 1 May 2026. Gov.uk says Form 4 should not be used if the property is rented privately.

The notice must also propose a start date that meets the rules in Note A of Form 4A:

• at least two months after the tenant receives the notice
• at least 52 weeks after the tenancy began or the last increase (sometimes 53)
• the first day of a rent period

Who decides whether a notice is valid

The Renters’ Rights Act 2025 added section 13B to the Housing Act 1988. Where a tenant applies to the First-tier Tribunal, the tribunal may decide whether a Section 13 notice is valid.

Form 4A also tells tenants they can refer the notice to the tribunal if they believe there is a problem with it, giving the example of a notice not served at least two months before the increase. So a tenant does not need to argue about the rent amount to challenge your notice.

You cannot decide for yourself that a mistake does not matter. If you are unsure whether a notice is valid, the practical choice is between re-serving now or risking a challenge later.

Common errors and what to do

The “likely risk” column is our general view, not a legal test. If the increase is large or the tenant has already raised the point, take advice.

How to re-serve a Section 13 notice

1. Stop relying on the first notice. Do not demand the new rent from its start date.
2. Work out a fresh start date. Count from when the tenant will receive the new notice. Use the Section 13 rent increase date calculator.
3. Complete a new Form 4A in full. Follow how to fill in Form 4A. Include every tenant, sign it, and keep all the pages.
4. Write a short covering letter. Explain that the new notice replaces the earlier one and that the earlier start date no longer applies. Keep it consistent with the form.
5. Serve it and keep proof. See how to serve a notice.

Does the 52-week clock restart?

An invalid notice does not increase the rent. The 52-week rule runs from when the tenancy began or from the last increase that actually took effect, not from the date of a failed notice. Do not record the failed notice’s start date as your “last increase”.

Timing impact: how much a mistake costs

The two-month notice period runs from the new notice, not the old one. The table shows the knock-on effect for a monthly tenancy with rent due on the 20th.

A week’s delay in the third row costs a further month at the old rent. The delivery allowance for post is our conservative planning buffer, not a statutory deemed-service rule.

Worked example: a notice on the old form

• The monthly tenancy began on Sunday 20 April 2025. Rent is £950, due on the 20th.
• There has been no increase.
• On Monday 3 August 2026, the landlord posted an old Form 4 proposing £995 from Sunday 20 September 2026.
• In October 2026, the landlord realises the mistake. The tenant has carried on paying £950.

The notice has two problems. It is not on Form 4A, and 20 September 2026 is less than two months after the tenant could have received a notice posted on 3 August. The landlord re-serves.

The new Form 4A gives 20 December 2026 in question 4.6. The original plan was 20 September 2026, so the mistake cost three months at the old rent: £45 a month, £135 in total. If the landlord had waited until after Tuesday 20 October 2026 to hand over the notice, the earliest date would move to 20 January 2027.

If the tenant had already started paying £995 because of the faulty notice, the landlord should take advice about the difference before going further.

Common mistakes

• Sending a correction letter instead of a new notice. You cannot amend a served notice by letter.
• Waiting to see if the tenant notices. The tenant can ask the tribunal to decide validity, and every month you wait delays a valid increase.
• Counting from the old notice. The two months run from receipt of the new notice.
• Copying the old date. A date that was valid in August may not work for a notice served in October.
• Treating unpaid amounts as arrears. If the notice was invalid, the tenant owes the old rent.

Frequently asked questions

Can I just change the date on the notice and give it back?

No. Serve a new, complete Form 4A with a valid date. Our Form 4A guide says the same.

Does re-serving count as my once-a-year increase?

A notice that never took effect has not increased the rent, so it does not reset the 52-week clock. Do not serve a second notice to get around a tribunal referral of a valid notice.

My Form 4 was served before 1 May 2026. Is it still valid?

Government guidance says that if you used Form 4 to give notice before 1 May 2026, the notice period and increase in the form still apply, even if the new rent starts after 1 May 2026.

What if the tenant has already referred the notice?

Let the tribunal deal with it. Read what happens if a tenant challenges a rent increase, and take advice before serving anything new.

Can the tenant and I agree to fix the mistake?

You can agree a lower rent or no increase in writing. You cannot agree a higher rent outside section 13. See rent increase letter vs Section 13 notice.

Next steps

• Recalculate your date with the free Section 13 rent increase date calculator.
• Create a correct notice on the Section 13 notice (Form 4A) page. It checks your dates before you download.
• Check which form applies in Form 4 vs Form 4A.

If you are in a dispute about a rent increase notice, speak to a solicitor; tenants can get advice from Shelter.