Statutory bars on serving a Section 21 notice
There are limited situations where the law prevents a landlord from serving a Section 21 notice at all, regardless of later compliance or how carefully the notice is drafted. These include cases where:
- The tenancy began less than four months ago.
- The tenancy is not an assured shorthold tenancy, as Section 21 applies only to ASTs.
- The property requires a licence, such as a house in multiple occupation or a property within a selective licensing area, and that licence was not in place when the notice was served, subject to any licence application or exemption that removes the restriction.
- A relevant local authority notice has been served (for example an improvement notice or emergency remedial action notice), which blocks Section 21 for a statutory period
Where any of these apply, a Section 21 notice cannot be served validly, regardless of how carefully it is prepared.
Deposit protection failures
If the landlord failed to protect the tenancy deposit in an authorised tenancy deposit protection scheme within 30 days of receipt, a valid Section 21 notice cannot be served.
The same applies where the landlord failed to provide the prescribed information to the tenant or relevant person within the same timeframe. If the deposit was mishandled, incorrectly credited towards the tenant’s rent or deductions were made outside the rules, the notice will also fail.
Unless the deposit has been repaid in full, including any amount credited towards the tenant’s rent, the landlord cannot serve a valid Section 21 notice. In these cases, there is still potential to pursue eviction. However, it is strongly recommended that you seek professional guidance before taking further steps.
Failure to provide prescribed documents
Under the Assured Shorthold Tenancy Notices and Prescribed Requirements (England) Regulations 2015 (the Regulations), a Section 21 notice is invalid if certain documents were not provided to the tenant before the notice was served.
Energy performance certificate (EPC)
The landlord must provide an energy performance certificate to the tenant. A failure to provide an EPC makes the Section 21 notice invalid. This requirement applies to ASTs granted or renewed where an EPC is legally required.
Gas safety certificate
Where the property has gas, the tenant must be given a valid gas safety certificate. Case law, including Trecarrell House Ltd v Rouncefield, confirmed that late service may be remedied in some circumstances, but failure to provide a certificate at all will invalidate the notice.
The landlord must also remain compliant with ongoing gas safety obligations throughout the tenancy, as failures can undermine reliance on Section 21 and risk exposure to enforcement action.
How to Rent guide
The tenant must have received the correct version of the government’s How to Rent guide before the Section 21 notice is served. If the landlord failed to provide the guide at the start of the tenancy, or provided an outdated version where a replacement tenancy was granted, the Section 21 notice will not be valid.
Incorrect notice form or notice period
A Section 21 notice must be served using Form 6A. Using an incorrect form or modifying the prescribed wording will invalidate the notice.
The notice period must also be correct. This depends on whether the tenancy is a fixed term tenancy or a periodic tenancy and on the tenancy period itself. An incorrect expiry date, an insufficient notice period or a notice that attempts to end an assured shorthold tenancy prematurely will fail at the possession hearing stage.
Failure to start possession proceedings within time limits
The government has confirmed transitional arrangements that allow landlords to continue relying on a Section 21 notice served before 1 May 2026. However, during this period, accuracy is critical. Any failure to meet the legal requirements for a valid notice may prevent landlords from relying on Section 21 at all.
Where a Section 21 notice is served before Section 21 is abolished on 1 May 2026, and the notice complies fully with the legal requirements, landlords may still progress possession under the existing route. Even then, the timeframe for issuing a court claim is tightly restricted.
In practice, landlords must start possession proceedings no later than 31 July 2026. Any notice that is not acted on by that date will expire and cannot be relied upon.
If proceedings are not issued within this timeframe, the notice will expire and cannot be relied upon. An invalid or expired notice cannot be corrected retrospectively and may leave landlords with no option but to proceed under the new statutory grounds regime.
Any Section 21 notice served on or after 1 May 2026 will have no legal effect. Attempting to rely on an invalid notice at that stage may result in the claim being dismissed and can expose landlords to enforcement action by the local authority.
Retaliatory eviction and local authority notices
A Section 21 notice is invalid if it was served following tenant complaints about the condition of the property and the local authority then served an improvement notice or emergency remedial action notice.
Once a relevant local authority notice has been served, the landlord cannot rely on Section 21 for a six month period. This applies even if the notice was otherwise compliant.
What happens if a Section 21 notice is invalid?
If a Section 21 notice is invalid, the county court will dismiss the possession proceedings. The landlord must then identify and correct the defect before attempting to serve a fresh notice, where that remains possible.
With the abolition of Section 21 approaching, any delay now is likely to mean missing the remaining window to rely on the no-fault route altogether. An invalid notice can therefore leave a landlord unable to proceed under Section 21 and forced instead to pursue possession under Section 8 grounds, with longer notice periods, higher evidential thresholds and greater court scrutiny.
How AST Assistance helps landlords
AST Assistance works exclusively with private landlords to provide specialist advice on Section 21 notices before they are served, identify compliance risks, and manage possession proceedings through the county court where required. We advise on notice validity, possession strategy, and enforcement, including where transitional deadlines apply under the Renters’ Rights Act.
For landlord-focused advice on these matters, contact AST Assistance on 01706 619 954, email info@ast-assistance.com, or use the online contact form to speak with our team.
