Section 13 Form 4A — The New Rent Increase Notice for 2026

From 1 May 2026, the only lawful way to raise rent on an assured periodic tenancy in England is by serving a Section 13 notice on the new prescribed Form 4A. The old Form 4 is abolished. Any contractual rent-review clause in a pre-existing AST falls away on commencement. This guide explains Form 4A in detail — what changed, how to complete it, how to evidence market rent, and what happens if the tenant refers it to the First-tier Tribunal.

What is Form 4A and why it replaced Form 4

Form 4A is the prescribed notice form for Section 13 rent increases under the Housing Act 1988 as amended by the Renters' Rights Act 2025. It replaces Form 4 (prescribed under the Assured Tenancies and Agricultural Occupancies (Forms) (England) Regulations 2015). The replacement was needed because the RRA 2025 introduced new restrictions on rent increases — notably the 12-month rule and the abolition of contractual review clauses — and Form 4 did not reflect these constraints or the new tenant information requirements.

Key changes from Form 4 to Form 4A

Feature	Old Form 4	New Form 4A
Frequency of increases	As per tenancy agreement or annual statutory fallback	Strictly once per 12-month rolling window — no exceptions
Contractual review clauses	Permitted alongside statutory route	All contractual review clauses overridden; Section 13 is the sole route
Tenant information	Basic summary of tribunal referral right	Expanded information on tenant rights, market rent concept, and tribunal process
Tenancy type	AST or Assured Tenancy	Assured Periodic Tenancy only
Notice period	One month (monthly) or six months (yearly)	Minimum two months in all cases
Market rent evidence	Not required on form	Landlord encouraged to retain evidence of market comparables

The 12-month rule

Under Section 13 as amended by the Renters' Rights Act 2025, a landlord may propose a rent increase no more than once in any 12-month period. The 12-month window runs from the date the last increase took effect (not the date of service). If you served your last increase on 1 June 2026 and it took effect on 1 August 2026, your next increase cannot take effect until 1 August 2027 at the earliest.

First increase after conversion

If your AST converted to an APT on 1 May 2026, the 12-month clock starts from the date of the last contractual rent increase that took effect before commencement. If rent was last increased on 1 January 2026, you cannot serve a Section 13 increase taking effect before 1 January 2027.

Minimum 2-month notice period

Form 4A requires a minimum of two months' notice regardless of the tenancy payment period. This is a change from the old regime where monthly tenancies required only one month's notice. The notice must specify the date from which the new rent takes effect, and that date must be at least two months after the date of service. The effective date must also be the first day of a period of the tenancy.

How to complete Form 4A step by step

Landlord details. Enter the full name and address of every landlord. If a company, use the registered name and registered office address.
Tenant details. Enter the full name of every tenant named on the tenancy. The notice must be served on all named tenants.
Property address. The full address of the let property including postcode, matching the tenancy agreement.
Current rent. State the current rent amount and the period it covers (e.g. £1,200 per calendar month).
Proposed new rent. State the proposed new rent amount. This must reflect a market rent — an excessive increase invites a tribunal referral and a determination that may be lower than your proposal.
Effective date. The date from which the new rent applies. Must be at least two months from the date of service, and must be the first day of a tenancy period.
Landlord's signature and date. Sign and date the form. If an agent is acting, include the agent's details and confirmation of authority.
Serve the notice. Serve on all named tenants. Keep a dated copy and proof of service.

How to evidence market rent

While Form 4A does not require you to attach market evidence, the First-tier Tribunal will expect it if the tenant refers the increase. Build your evidence file before serving the notice:

Rightmove / Zoopla / OnTheMarket comparables. Find 3–5 similar properties within 0.5 miles, let within the last 6 months, at a similar specification. Screenshot the listings with dates.
Lettings agent appraisals. Ask two local agents for a written rental valuation. Keep these on file.
Your own property's condition. Document any improvements since the last rent was set (new kitchen, new boiler, redecoration) with dated photos and receipts.
Council Tax band and EPC rating. The tribunal considers these as proxies for property quality.
Avoid punitive increases. The tribunal determines what the open market rent would be, ignoring tenant improvements and disregarding any scarcity premium. A proposed increase well above market will be adjusted downward — and you cannot withdraw once referred.

Tenant's right to refer to the First-tier Tribunal

The tenant has the right to refer a Section 13 notice to the First-tier Tribunal (Property Chamber) before the proposed effective date. The tribunal will determine the market rent for the property. Key points:

The tenant must apply to the tribunal before the effective date stated on the notice.
The tribunal determines the open market rent, ignoring tenant improvements and any scarcity premium in the local area.
The tribunal's determination replaces the landlord's proposed figure — it could be higher, lower or the same.
There is no fee for the tenant to refer to the tribunal.
Once referred, the landlord cannot withdraw the notice to avoid an unfavourable determination.

What happens at the Tribunal

The First-tier Tribunal will typically deal with the matter on paper, without a hearing, unless either party requests one. The tribunal panel (usually a legally qualified chair and a valuer) will:

Review the landlord's proposed rent and any evidence submitted.
Review the tenant's reasons for referral and any counter-evidence.
Inspect the property (either in person or by reviewing photographs and the EPC).
Consider comparable rents in the locality for similar properties.
Issue a determination specifying the market rent and the date from which it takes effect.
The determined rent takes effect from the date originally proposed or, if the tribunal considers it appropriate, from the date of the determination.

Practical tip

The best defence against a tribunal referral is a reasonable increase supported by documented comparables. If your proposed increase is in line with the local market, most tenants will not bother with a referral — and if they do, the tribunal will confirm your figure.

Get the Section 13 Rent Increase Pack

The LetSafe UK Section 13 Rent Increase Pack (LS-E-011, £19) includes the new Form 4A, a rent comparables evidence template, a 12-month timing calculator, a covering letter for the tenant, and guidance notes on tribunal preparation. It ships on 1 May 2026 and is available to pre-order now.

Frequently asked questions

Can I still use a contractual rent-review clause after 1 May 2026?

No. The Renters' Rights Act 2025 overrides all contractual rent-review clauses from 1 May 2026. The only lawful route to a rent increase is Section 13 via Form 4A. Any clause in a tenancy agreement purporting to allow a rent review outside Section 13 is void from commencement.

What if my tenant agrees to a rent increase without a Form 4A?

An informal agreement to increase rent is not enforceable from 1 May 2026. Even if the tenant verbally agrees or signs a side letter, the increase has no legal effect unless served via a valid Form 4A notice. If a dispute arises later, the tenant could reclaim the difference.

Can I increase rent more than once in 12 months if the tenant agrees?

No. The 12-month rule is mandatory and cannot be contracted out of, even with the tenant's written consent. One increase per 12-month rolling window is the absolute maximum.

What notice period applies to a weekly tenancy?

The minimum notice period under the amended Section 13 is two months in all cases, regardless of whether the tenancy is weekly, fortnightly or monthly. This is a change from the old regime.

Can the tribunal set a rent higher than my proposed increase?

Yes. The tribunal determines the open market rent, which could be higher than the figure you proposed. However, in practice this is rare — the tribunal will not increase rent beyond the landlord's proposal unless it is clearly below market level, and even then many panels cap at the landlord's figure. Do not rely on this outcome.

Does Form 4A apply in Wales?

No. Form 4A is prescribed for England only. In Wales, rent variations are governed by the Renting Homes (Wales) Act 2016 and use a separate prescribed form. See our Welsh Landlord Starter Pack for the correct Welsh documents.