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An invalid Form 4A does not increase the rent. The tenant can keep paying the old rent, and the landlord must start again with a new notice and a fresh two-month period. The usual errors are the wrong form, the wrong start date, short notice, or increasing rent too soon.
Why does validity matter?
From 1 May 2026, a landlord of an assured periodic tenancy in England must use Section 13 and Form 4A to increase rent. Government guidance says you must follow that process every time, even if the tenant has agreed. If the notice is defective, it has no legal effect.
(Source: Assured periodic tenancies: rent increases)
What mistakes make the notice invalid?
| Mistake | Why it fails |
|---|---|
| Wrong form | A Form 4 served on or after 1 May 2026, or a letter or email in place of Form 4A, is not the prescribed form |
| Start date not the beginning of a period | The new rent must start at the beginning of a tenancy period. Paying on a different day does not change that date |
| Less than two months’ notice | The period runs from service, not from the date you printed the form |
| Increase in the first year | You cannot increase the rent in the first year of the tenancy |
| Second increase within a year | The next increase cannot take effect until at least a year after the last increase took effect |
| Relying on a rent review clause | A clause cannot be used for a new increase after 1 May 2026. An increase agreed under a clause before that date, but taking effect after it, does not apply |
The Court of Appeal in Mooney v Whiteland [2023] EWCA Civ 67 held a notice invalid where the landlord used the tenant’s usual Friday payment day instead of the Monday when the weekly period began. The judgment is public on the National Archives case-law site.
Names and addresses that do not match the tenancy, missing prescribed wording, or an unsigned form can also be challenged. Government guidance for tenants lists the same validity points: correct notice period, 52-week gap, correct start date, correct details, correct form, and the landlord’s signature.
(Source: Assured periodic tenancies: rent increases; Apply for an open market rent determination; [Mooney v Whiteland [2023] EWCA Civ 67](https://caselaw.nationalarchives.gov.uk/ewca/civ/2023/67))
Can I correct a bad notice?
No. Serve a new Form 4A with a new start date that meets every timing rule. See how to complete Form 4A step by step.
Generate a Form 4A with the date checks built in. Use the free Form 4A generator
Last reviewed: 8 October 2026.
Frequently asked questions
What are the most common Form 4A mistakes?
Using the old Form 4 after 1 May 2026, giving less than two months' notice, setting a start date that is not the beginning of a tenancy period, increasing rent in the first year, or proposing a second increase within a year.
Can a landlord correct an invalid notice?
The landlord must serve a new Form 4A with a fresh notice period. An invalid notice cannot be patched or backdated.
Does the notice period run from posting or from service?
From service. If you post the form, allow time for delivery when you set the start date.
Does a rent review clause still work?
Not for a new increase after 1 May 2026. Government guidance says an increase agreed under a rent review clause before that date, but taking effect after it, does not apply.
This article is provided for informational purposes only and does not constitute legal advice. LLCR is a compliance management platform, not a law firm. For advice specific to your situation, consult a qualified solicitor.
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