Section 21 notice invalid: reasons and what to do

A Section 21 notice served on or after 1 May 2026 is not valid. A notice served before that date can still be challenged on up to 16 legal grounds.

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Common questions

What makes a Section 21 notice invalid?
A Section 21 notice is invalid if it was served on or after 1 May 2026, or if a legacy pre-May 2026 notice fails one of the legal requirements. Common defects include the wrong form, too little notice, service in the first four months, an expired notice, deposit protection or prescribed information failures, missing EPC, gas safety or How to Rent documents, required licensing gaps, prohibited payments, or retaliatory eviction under section 33 of the Deregulation Act 2015.
Can a landlord fix a defective Section 21 notice?
Sometimes. For a legacy notice served before 1 May 2026, some defects could be fixed by remedying the problem and serving a new notice, for example returning a deposit or providing missing prescribed documents before re-serving. But new Section 21 notices cannot be served on or after 1 May 2026, so after that date the landlord must usually use Section 8 and prove a legal ground instead.
Do I have to leave on an invalid Section 21 notice?
No. An invalid Section 21 notice is not an eviction and cannot support a possession order. Even where a notice is valid, you do not have to leave until the landlord obtains a county court possession order and, if needed, a county court bailiff enforces it.
What should I do if my Section 21 notice is invalid?
Keep the notice and all tenancy documents, run the Section 21 checker to identify the exact defects, and do not hand back the keys just because the notice asks you to leave. If court papers arrive, file a defence by the deadline and get housing advice from Shelter, Citizens Advice, or a housing solicitor.

Use the interactive checker on getrentersrights.com for the full step-by-step result.