The Section 13 procedure existed before the Renters' Rights Act 2025, but it was rarely used because most landlords increased rent at the end of a fixed-term AST by offering a new tenancy at a higher rate, or by including a rent review clause. Both of those routes are gone. All new tenancies are now Periodic Assured Tenancies (no fixed terms), and rent review clauses are void, Section 13 is the only lawful way to increase rent.
Understanding this procedure correctly is important not just for compliance, but because errors in the Section 13 process, wrong form, insufficient notice period, or serving before 12 months is up, mean the proposed increase does not take effect and you must start again.
The Section 13 procedure, step by step
Follow these steps exactly for a valid rent increase:
- Step 1, Obtain Form 4A: Download the current version of Form 4A (Notice of Increase of Rent) from gov.uk, always use the current version; an outdated form can invalidate the notice
- Step 2, Complete the form: Enter the current contractual rent, the proposed new rent, and the proposed effective date of the increase
- Step 3, Calculate the effective date: The effective date must be at least 2 months after the date the notice is served on the tenant
- Step 4, Serve the notice: Serve Form 4A on the tenant by first-class post (add 2 working days for deemed receipt), hand, or email if the tenancy agreement expressly permits email service
- Step 5, Wait for the tenant's response: The tenant must refer the notice to the First-tier Tribunal before the effective date if they wish to challenge it. If they do not refer it, the new rent takes effect automatically on the effective date
- Step 6, Update your records: Once the increase takes effect, update your rent account records and any standing order mandates
The 12-month timing rule
Section 13 notices are subject to a strict timing restriction:
- A Section 13 notice cannot take effect less than 12 months after the last rent increase
- For a new tenancy: the first Section 13 notice cannot take effect less than 12 months after the tenancy start date
- You cannot serve a second Section 13 notice while the first has not yet taken effect
- The 12-month restriction runs from the effective date of the last increase, not from the date you served the notice
- Example: if a rent increase took effect on 1 March 2026, the earliest effective date for the next Section 13 notice is 1 March 2027 (giving at least 2 months' notice means the notice must be served by 1 January 2027)
First-tier Tribunal referral, what to expect
The tenant can refer any Section 13 notice to the First-tier Tribunal (Property Chamber) before the effective date:
- The FTT determines the 'open market rent', what a willing tenant would pay on the open market for the property on the date of the determination
- Under the Renters' Rights Act 2025 the tribunal cannot set the rent higher than the figure proposed in your notice, it can only confirm or reduce it. There is therefore no upside risk to the tenant in referring
- Evidence to prepare: 3 to 5 comparable rental listings of similar size, location, and condition; letting agent market reports; historical rent data. The most useful comparables are lets within 0.5 miles, same property type, same number of bedrooms, completed in the last 6 months
- The tribunal's determination takes effect from the original proposed effective date on Form 4A, there is no gap
- The referral suspends the proposed increase until the tribunal decides, the current rent remains in force during the tribunal process
Unenforceable rent increase clauses
The following clauses are void in any Periodic Assured Tenancy Agreement, they cannot substitute for Section 13:
- Fixed annual percentage increase: 'Rent increases by 3% per annum', void. Section 13 must be used
- CPI or RPI escalator: 'Rent increases annually in line with CPI', void. Section 13 must be used
- Review to market rent clause: A contractual right to review rent to market rate, void as a substitute for Section 13
- Landlord's notice to increase without Form 4A: A generic letter saying 'I am increasing your rent to £X from Y date' is not a valid Section 13 notice if it does not use Form 4A
- A deed of variation by mutual agreement is lawful, but only if the tenant genuinely consents. If there is any pressure or misrepresentation, the agreement can be voided
Timing tactics
Four practical timing points that make a Section 13 increase land cleanly:
- Serve in month 11 for an effective date in month 13, this gives the tenant ample notice and starts the 12-month clock cleanly
- Pick a month that does not coincide with a peak move-out season, tenants are less likely to leave when alternatives are scarce
- Budget for a possible tribunal referral, build in a two-month buffer so a tribunal assessment does not push your rise into month 15
- Document the comparables on the day of service, a tribunal panel ignores comparables gathered after the fact
What happens if you get Section 13 wrong
The consequences of a defective Section 13 notice:
- An invalid Section 13 notice means the proposed increase does not take effect, the current rent remains in force
- If you collect the higher rent after an invalid notice, the tenant can recover the overcharge as an unlawful deduction
- You must start the process again with a valid Form 4A, subject to the 12-month timing rule from the last valid increase
- A defective Section 13 notice is not a criminal offence, but unlawfully collecting rent above the current contractual level is actionable
- The most common errors: using an outdated form, insufficient notice period (less than 2 months), and serving before 12 months since the last increase
Frequently asked questions
Can I increase rent by agreement with the tenant without using Form 4A?+
Yes, a genuine written agreement between landlord and tenant to increase the rent (a deed of variation or a letter countersigned by the tenant) is lawful. However, this is only valid if the tenant genuinely agrees, you cannot use pressure, misrepresentation, or threats of possession to obtain consent. In practice, most rent increases should go through the Section 13 / Form 4A route because it is transparent, verifiable, and protects both parties.
Can the First-tier Tribunal set a rent higher than I proposed?+
No. Under the Renters' Rights Act 2025 the tribunal sets the rent at what comparable open-market properties achieve, but it cannot set a rent higher than the figure proposed in your Form 4A notice. If the tribunal's assessment is lower than your notice, the lower figure binds. Because there is no upside risk to the tenant in referring, always propose a figure you can support with comparable evidence.
How much notice must I give for a Section 13 rent increase?+
At least 2 months' written notice on Form 4A. The effective date stated on the form must be at least 2 months after the date the notice is served on the tenant. If served by first-class post, add 2 working days for deemed receipt. If you serve on 1 January, the earliest effective date is 4 March (1 January + 2 working days receipt + 2 months). Always calculate from the deemed receipt date, not the date you posted the notice.
Do I need to use Form 4A or can I write my own notice?+
Form 4A is the prescribed form for Section 13 notices under the Housing Act 1988. You must use it, a generic letter purporting to increase rent is not a valid Section 13 notice. Download the current version from gov.uk before serving; the form is updated periodically and an outdated version may be invalid.
This page is drafted against the legislation below. Always check the current text of the law before acting.
- Renters' Rights Act 2025 (legislation.gov.uk)
- Housing Act 1988 (legislation.gov.uk)
LetSafe UK provides landlord notice templates, compliance documents, and legal guides for England and Wales.