Form 4A is the prescribed 'Landlord's notice proposing a new rent for assured tenancies in the private rented sector'. From 1 May 2026 it is the only valid way to increase rent on an assured periodic tenancy in England without the tenant's voluntary agreement. It replaces the old Form 4 used for the Section 13 process. The increase still runs under Section 13 of the Housing Act 1988, but the form and the rules around it changed under the Renters' Rights Act 2025.

How much notice does Form 4A require?

At least 2 months. You must give the tenant the completed Form 4A at least 2 months before the date you want the new rent to start. You cannot make the increase effective sooner, and you cannot increase rent in the first 12 months of the tenancy or more than once a year.

Can the First-tier Tribunal set my rent higher than I asked for?

No. This is the key change under the Renters' Rights Act 2025. The Tribunal can only set the new rent at, or below, the figure you proposed on Form 4A. A tenant can no longer be ordered to pay more than the landlord asked for, which removes the old deterrent that discouraged tenants from challenging.

When does the new rent start if the tenant challenges it?

From the date of the Tribunal's determination, not your proposed date. The Renters' Rights Act ended the backdating of rent increases. The Tribunal can also defer the start of the increase by up to a further 2 months where the tenant would otherwise suffer undue hardship.

Do I still have to use Form 4A if the tenant has already agreed the increase?

If the tenant genuinely agrees a new rent in writing, you can record that by agreement rather than imposing it. But any rent review clause in the tenancy agreement is void from 1 May 2026, so the only route to force an increase the tenant has not accepted is a valid Form 4A under the Section 13 process.

What happens if I serve Form 4A within 12 months of the previous increase?

A Form 4A with an effective date within 12 months of the previous increase is void. The tenant can refer it to the First-tier Tribunal, which has no power to set a new rent before the 12-month period has expired. The tenant should continue paying the old amount, the new figure has no legal force. You must wait until the full 12 months have elapsed, then re-serve with a correct effective date.

When the new rent takes effect, the tenant keeps paying the old amount. What do I do?

The new rent applies automatically from the effective date whether or not the tenant acknowledges it. Every payment shortfall from that date accumulates as rent arrears. Once arrears reach three months' rent, at both the date of the Section 8 notice and the court hearing, Ground 8 of the Housing Act 1988 applies and possession is mandatory. Document every payment carefully against the new rent figure from the effective date, and serve a Section 8 notice once the three-month threshold is reached.

Form 4A Rent Increase 2026: How to Raise Rent the New Way

In short: Since 1 May 2026, the only lawful way to increase rent on an assured periodic tenancy in England without the tenant’s agreement is the prescribed Form 4A, the “Landlord’s notice proposing a new rent”. It runs under the Section 13 process in the Housing Act 1988, but the Renters’ Rights Act 2025 changed the rules: at least 2 months’ notice, a maximum of once a year, no increase in the first 12 months, and the increase must reflect the open market rent. The biggest change is in the tenant’s favour, if a tenant challenges the increase at the First-tier Tribunal, the Tribunal can only set the rent at or below the figure you proposed, and the new rent applies from the date of the determination, not backdated.

If you have raised rent on a periodic tenancy before, the headline news is that the form changed. The old Form 4 is gone. From 1 May 2026 you must use Form 4A, published on GOV.UK for use on or after 1 May 2026. Serve an outdated form and the notice is invalid, you lose months and have to start again.

This guide is the step-by-step process: who it applies to, how to fill in and serve Form 4A, the notice period, and what happens if the tenant takes it to the First-tier Tribunal. For the wider context of the reforms, read the complete Renters’ Rights Act guide and the periodic tenancy guide.

Form 4A vs the Old Section 13 Process

The legal mechanism has not changed name. Rent increases on an assured periodic tenancy still run under Section 13 of the Housing Act 1988. What changed is the prescribed form and the rules wrapped around it.

	Before 1 May 2026	From 1 May 2026
Prescribed form	Form 4	Form 4A
Minimum notice (monthly tenancy)	1 month	2 months
Maximum frequency	Once every 12 months	Once every 12 months (unchanged)
First-year increase	Allowed	Not allowed
Tribunal can set rent above your proposal	Yes, a real risk for tenants	No, capped at your proposed figure
When a challenged increase starts	Could be backdated	From the Tribunal’s decision date

If you are still working from a template or a guide that references “Form 4”, it is out of date. Use Form 4A.

Who Form 4A Applies To

Form 4A applies to assured periodic tenancies in the private rented sector in England, which, since 1 May 2026, is effectively every private tenancy, because fixed terms were abolished and all assured shorthold tenancies converted to periodic assured tenancies on that date.

You use Form 4A when:

You let residential property in England (Scotland and Wales have separate regimes)
The tenancy is an assured periodic tenancy
The tenant has not voluntarily agreed a new rent in writing
It has been at least 12 months since the tenancy started or since the last increase took effect

You do not need Form 4A if the tenant genuinely agrees a new figure in writing, though you cannot rely on a rent review clause to do this, as those clauses are void from 1 May 2026.

How to Increase Rent Using Form 4A

Follow these steps in order. Each one matters: a defect at any stage can invalidate the notice.

Step 1, Confirm you are allowed to increase now

Check two dates before you do anything:

The tenancy must have been running for at least 12 months, or it has been at least 12 months since the last increase took effect. You cannot increase rent in the first year of a tenancy.
You can only increase rent once in any 12-month period.

If either test fails, you must wait. Serving early makes the notice invalid.

Step 2, Set a rent that reflects the open market

The proposed rent must be in line with the open market rent, defined by GOV.UK as “the rent that you would expect to receive if you were to relet the property on the open market”.

Gather evidence now, because you may need it at a Tribunal later:

Comparable lettings within roughly one mile on Rightmove and Zoopla
A letting agent’s written rental valuation
Dated screenshots of similar advertised properties

Because the Tribunal can no longer set the rent above your proposed figure, your proposed rent is now effectively a ceiling, not a starting point for negotiation. Pitch it at a defensible market level, not optimistically high, because if you over-reach the Tribunal will simply set a lower figure.

Step 3, Download a fresh copy of Form 4A

Download the current Form 4A, “Landlord’s notice proposing a new rent for assured tenancies in the private rented sector” from the GOV.UK assured tenancy forms page. Always take a fresh copy for each notice, using a saved or outdated version risks serving a superseded form.

Step 4, Complete the form accurately

Fill in every required field:

The full names of all landlords and all tenants, exactly as on the tenancy agreement
The full property address
The current rent and what it includes
The proposed new rent and the date it is to take effect
The notice must give the tenant at least 2 months before that effective date

The effective date should align with the start of a rental period. If rent is due on the 1st, set the new rent to begin on the 1st.

Step 5, Serve the notice correctly

Serve Form 4A by a method that gives you provable delivery:

By hand, ideally with a witness, keeping a dated note
First-class post, allow extra working days for deemed service
By email, only if the tenancy agreement permits service by email or the tenant has agreed to it in writing

Record the date and method of service. Proof of service is your evidence if the tenant later disputes the notice.

Step 6, Wait out the notice period

The new rent cannot take effect until at least 2 months after service. During this window the tenant can either accept the new rent (by paying it, or saying nothing and paying when it falls due) or refer it to the Tribunal.

Step 7, Respond if the tenant challenges

If the tenant applies to the First-tier Tribunal before the effective date, do not impose the new rent until the Tribunal decides. See the next section.

Building an Open Market Rent Evidence File

The proposed rent is the single most important number on the form. Pitch it too high and a tenant challenges, the Tribunal caps the rent at the market figure and you lose months. Pitch it at a defensible, evidenced level and most tenants accept without challenge. Build a written evidence file before you serve.

Comparable lettings (comparables): Search Rightmove and Zoopla for properties let in the last six months that are materially similar to yours, same area (within half a mile if possible), same type (house or flat), same bedroom count, comparable condition, and the same furnished status. Take dated screenshots of each listing. Aim for at least three comparables at or above your proposed figure and note any that are lower. The Tribunal weighs a cluster of comparables, not a single data point.

Professional valuation letter: Ask a local ARLA-accredited letting agent for a written rental valuation. It costs nothing from agents active in the area. The letter should state: the property address, the date, the market rent range they would expect if the property were re-advertised today, and the comparables they used. Keep the original. A signed letter from a named professional carries more weight at Tribunal than screenshots alone.

Historical rent context: If your rent has not been increased for several years, the gap between what you charge and the current market is likely substantial. Present the history, original rent, date of any previous increase, and how the proposed figure compares to today’s market. A Tribunal panel looks at what an independent landlord would accept from a new tenant, not how far the increase is from the old rent.

Store everything in a single dated folder per property: screenshots, the agent’s letter, and any area rental reports. If the case goes to Tribunal, hand this in as your evidence bundle. If the tenant backs down on seeing a well-evidenced figure, you have it on file for next time.

If the Tenant Challenges at the First-Tier Tribunal

A tenant who believes the proposed rent is above the open market rate can refer the increase to the First-tier Tribunal (Property Chamber) before it takes effect. Two changes under the Renters’ Rights Act 2025 make this far more tenant-friendly than the old system:

The Tribunal cannot set the rent higher than you proposed. GOV.UK guidance confirms the policy: “tenants never pay more than what the landlord asked for.” Under the old rules the Tribunal could set a higher figure, which deterred many tenants from challenging. That deterrent is gone.
No backdating. A rent increase decided by the Tribunal applies from the date of the determination, not from your originally proposed date. The Tribunal can also defer the increase by up to a further 2 months in cases of undue hardship.

The practical effect: a challenge can only ever reduce your proposed figure or delay when it starts. There is no longer any upside for you in a Tribunal referral, so the only sensible strategy is to propose a fair, evidenced market rent in the first place. Bring your comparable-rent evidence to the hearing, the Tribunal assesses what the property would fetch on the open market.

When the Tenant Ignores the New Rent

Once the effective date passes, the new rent applies automatically, whether or not the tenant acknowledges it in writing or in conversation. If the tenant continues paying the old amount, every payment shortfall accumulates as rent arrears from the effective date.

Keep a precise rent ledger from the outset:

Record each payment with the date received and the exact amount
Calculate the shortfall against the new rent for each payment period
Carry forward the cumulative arrears total

Under Ground 8 of the Housing Act 1988, once rent arrears reach three months’ worth at both the date you serve the Section 8 notice and the date of the court hearing, possession is mandatory, the court must grant it. A tenant who silently continues paying the old rent can therefore create a clear Ground 8 eviction route.

Suggested escalation:

Month 1 shortfall, write to the tenant confirming the effective date and that the new rent applies. Keep a copy.
Month 2 shortfall, serve a formal written arrears notice, stating the cumulative amount owed and the deadline to pay.
Approaching 3 months, consider serving a Section 8 notice under mandatory Ground 8 alongside discretionary Ground 10 (some arrears below the mandatory threshold), so you are covered even if a payment partially reduces the balance.

Document everything, emails, letters, payment records. The tenant not paying rent guide covers the full escalation process including court fees and timelines.

Form 4A in Houses in Multiple Occupation (HMOs)

Form 4A applies to each individual assured tenancy, not to the property as a whole. In an HMO where each room is let on a separate tenancy agreement, the most common structure for self-managing landlords, you need a separate Form 4A for each tenant whose rent you want to increase.

Each notice must name the relevant tenant, the room address (property address plus room number or description), the current and proposed rent for that room, and its own effective date. The 12-month frequency limit applies per tenancy, not per property, so you can increase different rooms at different points in the year, provided each tenant’s tenancy has been running for at least 12 months since the last increase.

If the HMO is let on a single joint tenancy covering the whole house, one Form 4A naming all joint tenants on the agreement is the correct approach. Omitting any joint tenant from that notice makes it defective.

Common Mistakes That Invalidate a Form 4A

Using the old Form 4 instead of Form 4A, automatically invalid from 1 May 2026
Giving less than 2 months’ notice, the most frequent error
Increasing within the first 12 months of the tenancy, or twice in one year
Misnaming the tenants or landlord, names must match the agreement
An effective date that does not align with a rental period
No proof of service, leaves you unable to defend the notice
Relying on a rent review clause, these are void; only Form 4A works

Any one of these can mean starting the whole two-month process again.

A Note on Templates and the Old Section 13 Form

If you have previously downloaded a “Section 13 / Form 4” rent increase template, treat it as superseded. The statutory wording, the form reference, and the notice period have all changed. Always generate a fresh Form 4A from GOV.UK. Our rent increase template page and the step-by-step rent increase guide cover the mechanics; cross-check any template against the current GOV.UK Form 4A before serving.

What to Do Now

Diarise the 12-month anniversary of each tenancy (or last increase) so you know the earliest date you can serve.
Build a market-rent evidence file per property, comparables and a valuation.
Bookmark the GOV.UK Form 4A page and download fresh each time.
Set your proposed rent defensibly, the Tribunal can only go down from it, never up.
Keep proof of service for every notice you serve.

A fair, well-evidenced increase served on the correct form is rarely worth challenging. Get the process right once and rent reviews become routine.

For the full set of compliance steps across the reforms, download our free Renters’ Rights Act compliance checklist, and read the periodic tenancy guide and the Renters’ Rights Act timeline for how rent increases fit into the wider 2026 framework.

Related guides: