Since 1 May 2026, landlords increasing rent on an assured periodic tenancy in England's private rented sector must use the statutory Section 13 process and Form 4A.

For these tenancies, contractual rent review clauses no longer provide an alternative route. A letter is not enough. An email setting out the same information is not enough. Even an increase the tenant has already agreed to in conversation must still go through the formal process.

That narrowing has a consequence many landlords haven't yet absorbed. The rent review used to be a negotiation that happened at renewal. It is now a procedural exercise with a prescribed form, fixed timing rules and a tribunal route for the tenant and an error in any one element can mean the increase does not take effect as intended.

This guide covers the Form 4A process, the timing rules, how tribunal challenges work, and the mistakes that most often cause problems.

Scope: This covers assured tenancies in England's private rented sector. Housing is devolved, so Scotland, Wales and Northern Ireland operate separate regimes. Social housing assured tenancies let by Private Registered Providers follow different rules until at least 2027.

Section 13 Is the Required Route

Section 13 of the Housing Act 1988, as amended by the Renters' Rights Act 2025, is the mechanism for increasing rent on a private assured periodic tenancy in England.

Three consequences follow:

1. Rent review clauses can no longer be used to increase rent on private assured periodic tenancies. A contractual provision purporting to raise rent automatically whether by a fixed percentage, an index such as CPI or RPI, or a stepped schedule cannot be used for this purpose.

2. Informal agreements are not enforceable as increases. If you and your tenant agree a new figure over the phone and they start paying it, that agreement has no statutory force.

3. The process applies even to agreed increases. GOV.UK is explicit that the Section 13 process must be followed every time, including where the tenant has already agreed.

There is nothing preventing a conversation first. GOV.UK in fact recommends discussing a proposed increase with the tenant before serving. But the conversation supplements the process; it does not replace it.

Form 4A: The Prescribed Notice

The notice must be served on Form 4A: Landlord's notice proposing a new rent for assured tenancies in the private rented sector, published on GOV.UK.

Do Not Use Form 4 for Private Renting

This is the single most avoidable error in the whole process.

Form 4 still exists, but since 1 May 2026 it applies only to social housing assured tenancies where the landlord is a private registered provider. GOV.UK states plainly on the forms page: do not use this form if the property is rented privately you should use Form 4A. Form 4A itself carries the same instruction in reverse: it is for use in the private rented sector in England only.

Anyone working from a template pack, a bookmarked download or a guide written before May 2026 is likely to be pointed at Form 4. Check the form number before you serve, not after.

For assured agricultural occupancies in the private rented sector, the equivalent is Form 5A rather than Form 4A.

Do Not Alter the Wording

GOV.UK's guidance on prescribed forms is direct: do not change the wording unless the form itself says you can. Changing the prescribed wording can put the validity of the notice at risk.

That means using the published form rather than reformatting it into house style, condensing sections that look irrelevant, or rebuilding it inside a template system. The form can be completed electronically or by hand the point is that the prescribed wording stays intact.

Getting the Form

Form 4A is published free on GOV.UK's assured tenancy forms page. Download it from there rather than from a third-party source, so you are working from the current version.

The Timing Rules

Three rules govern when a Section 13 notice can be served and when the increase can take effect.

Once a Year, Maximum

Rent can only be increased once in any twelve-month period. GOV.UK's landlord guidance states this plainly, and it applies across the transition an increase that took effect before 1 May 2026, whether by the old Form 4 or by a rent review clause, still starts the clock.

So if the rent last rose on 1 February 2026, the next increase cannot take effect before 1 February 2027, regardless of which mechanism produced the earlier rise.

Not in the First Year

Rent cannot be increased during the first year of a tenancy.

This is the rule with the biggest operational consequence, and it's frequently missed. A tenancy let below market cannot be increased through the Section 13 process during that first year. Pricing at the point of letting is now a decision you live with for a full twelve months.

At Least Two Months' Notice

The completed Form 4A must be given to the tenant at least two months before the new rent is due to start.

Work backwards from the date you want the increase to take effect, and build in time for service. If you are posting the notice, allow for transit the two months runs from service, not from the date you put it in the postbox.

Serving the Notice

The notice must be served using a method permitted by the applicable tenancy and service requirements. Form 4A provides for service in person, by post and, where permitted, by email.

The email condition matters. If your tenancy agreement has no service clause covering email, emailing the notice may not satisfy the requirements for valid service. This is worth checking across your template stock a missing service clause is a small drafting gap with a large consequence.

Whatever method you use, keep evidence of service. If the increase is later disputed, the date of service determines whether the notice period was met.

If the Tenant Disagrees: The First-Tier Tribunal

There are two distinct routes to the First-tier Tribunal, and they answer different questions. One challenges a proposed increase. The other challenges the rent that was set at the start of the tenancy.

Challenging a Section 13 Increase

A tenant who believes the proposed rent exceeds the open market rent what the property would achieve if newly let on the open market can apply to the First-tier Tribunal to determine the rent. The application must be made before the proposed new rent is due to start.

Two features of the current framework matter:

1. The tribunal cannot set the new rent above the amount proposed by the landlord.
   The amount determined is the lower of the open market rent and the rent proposed in the Section 13 notice. Previously a tenant risked the tribunal setting a higher figure than the landlord had asked for, and that removes one of the major deterrents that existed under the previous framework.

2. Increases are no longer backdated.
   The new rent applies from the date of the tribunal's determination rather than the date in the notice. Where the tribunal is running behind, the tenant continues paying the old rent throughout.

The tribunal can also defer the increase by up to a further two months in cases of undue hardship.

Challenging the Initial Rent Within Six Months

Separately, a tenant can apply to the First-tier Tribunal during the first six months of a tenancy if they believe the initial rent is excessive.

This is not a challenge to an increase it is a challenge to the rent that was set when the tenancy began. HMCTS guidance and the tribunal's application form both treat it as a distinct route.

The practical implication for landlords and agents is that an initial rent set well above local market level carries its own exposure, independent of anything that happens at review time. Combined with the prohibition on increases during year one, initial pricing now cuts both ways.

Application requirements and any fees are set out in the tribunal's current guidance on applying for an open market rent determination.

Building Defensible Market Evidence

If a notice is challenged, the question before the tribunal is what the property would achieve if relet on the open market. Your proposed figure needs to be supportable on that basis.

What that means in practice:

• Comparable local listings, captured at the time you set the figure rather than reconstructed afterwards

• Genuinely comparable properties similar size, condition, location and specification, not simply the highest asking rents in the postcode

• A record of the reasoning, including any property improvements that justify a figure above the local baseline

• Current data. Old comparables are unlikely to provide strong evidence of a property's current open market rent

The operational implication is that market evidence needs capturing as part of the review process, not assembled once a tenant files an application. By that point the listings you relied on may have expired.

Common Mistakes That Can Make a Rent Increase Ineffective

Using Form 4 instead of Form 4A. A wrong-form error, and a genuine validity risk.

Altering the prescribed wording. Reformatting or condensing the form puts validity at risk.

Serving too soon after the last increase. The twelve-month rule counts increases made before 1 May 2026, including those made under rent review clauses.

Increasing in the first year. Not permitted through the Section 13 process, however the tenancy is priced.

Insufficient notice. Two months minimum, calculated from service. A late notice generally means the intended effective date cannot be achieved.

Service by a method the tenancy agreement does not permit. Email service in particular depends on the agreement allowing it.

Relying on a rent review clause. No longer available as a route for private assured periodic tenancies.

Relying on an informal agreement. Not enforceable as an increase without the Section 13 process.

Transitional Rules for Pre-May 2026 Increases

Three transitional points still arise:

Form 4 notices given before 1 May 2026 remain effective. Where notice was given on the old form before commencement, the stated notice period and increase still apply, even if the new rent starts after that date. The tenant retains the right to challenge at the tribunal.

The twelve-month gap counts backwards across the transition. A further increase cannot take effect until at least a year after the last one, including increases that took effect before 1 May 2026.

Rent review clause increases agreed before commencement do not apply if they take effect afterwards. Where a rent review clause was used before 1 May 2026 to agree an increase taking effect after that date, the increase does not apply.

What This Means for Property Teams

The move from renewal-based reviews to a statutory annual cycle changes the operational requirement in four ways.

1. Reviews need their own calendar:
   With no fixed terms and no renewal date, nothing prompts a rent review automatically. Each tenancy needs a diarised annual review window based on its own anniversary or last increase date.

2. Notice dates must be calculated backwards:
   Two months' notice, served correctly, means the Form 4A has to be prepared and served well ahead of the target date. Late service pushes the increase back.

3. Market evidence has to be captured at decision time:
   Not when a challenge arrives.

4. Initial pricing carries twelve-month consequences:
   With no increase permitted in year one and a tenant route to challenge the initial rent in the first six months, the figure set at letting matters more than it used to.

Portfolio-wide, this is a tracking problem: last increase date, next eligible date, notice service date, target effective date, and the evidence supporting each figure. Systems that handle rent collection and payment tracking as structured records make those dates visible rather than leaving them in individual diaries.

Conclusion

Section 13 turned rent increases from a negotiation into a procedure. The figure still reflects the market, but everything around it the form, the timing, the service method, the evidence is now prescribed, and an error in any one element can stop the increase taking effect.

The pattern that works is unglamorous: review annually, evidence the figure against current market comparables, serve the right form on time, and keep proof of service.

The riskier pattern is allowing rent to fall materially below market over several years, then attempting a large correction without current market evidence and without preparation for a possible tribunal challenge.

For the wider picture of what changed on 1 May 2026, see our guide to property management in England. For the possession side of the same reforms, see our guide to Section 8 grounds for possession.

Frequently Asked Questions

1. How Do I Increase Rent Legally in England in 2026?
Serve Form 4A, the prescribed Section 13 notice, on your tenant at least two months before the new rent is due to start. Rent can only be increased once a year, and not during the first year of the tenancy. Rent review clauses can no longer be used and informal agreements are not enforceable as increases — the Section 13 process must be followed every time, including where the tenant has already agreed.

2. What Is Form 4A and Where Do I Get It?
Form 4A is the prescribed notice proposing a new rent for assured tenancies in the private rented sector in England. It is published free on GOV.UK's assured tenancy forms page. Do not use Form 4 — since 1 May 2026 that form applies only to social housing assured tenancies let by private registered providers, and GOV.UK warns explicitly against using it for privately rented property.

3. Can I Increase Rent During the First Year of a Tenancy?
No. Under the current rules for assured periodic tenancies in England's private rented sector, rent cannot be increased during the first year of the tenancy. After the first year, it can generally be increased only once every twelve months, using the Section 13 process and Form 4A with at least two months' notice.

4. How Often Can I Increase the Rent?
Once in any twelve-month period. The rule counts increases that took effect before 1 May 2026, including those made under rent review clauses. If the rent last rose in February, the next increase cannot take effect until the following February.

5. Can a Tenant Challenge a Rent Increase in England?
Yes. A tenant who believes the proposed rent exceeds the open market rent can apply to the First-tier Tribunal before the new rent is due to start. The tribunal cannot set the new rent above the amount proposed by the landlord, and the new rent applies from the date of determination rather than being backdated. The tribunal can also defer the increase by up to two further months in cases of undue hardship. Separately, a tenant can apply for an open market rent determination during the first six months of a tenancy if they believe the initial rent is excessive.

Important Notice

This article applies to England only. Housing law is devolved and the position differs in Scotland, Wales and Northern Ireland.

Information was accurate as at 17 August 2026 and reflects the Renters' Rights Act 2025 as commenced on 1 May 2026. Prescribed forms, notice periods, tribunal procedures and any applicable fees may change as further regulations and guidance are made. Different rules apply to social housing assured tenancies let by Private Registered Providers, to which the Renters' Rights Act changes will not apply until 2027 at the earliest.

Always download the current version of Form 4A from GOV.UK and check the current position before serving notice.

This content is general information only and does not constitute legal advice. RIOO is not a law firm. For advice on a specific tenancy or a contested rent increase, consult a qualified housing solicitor or regulated adviser.