From 1st May 2026, the rules governing rent increases in the private rented sector changed fundamentally. Contractual rent review clauses, the kind included as standard in most assured shorthold tenancy agreements for the past three decades, no longer have any legal effect. If a landlord wishes to increase rent, there is now a single lawful route: the Section 13 procedure, using the prescribed Form 4A. This article explains how the procedure works, what the notice must contain, how to serve it correctly, what happens when a tenant challenges an increase at the First-tier Tribunal, and the mistakes landlords are already making.
Why contractual rent review clauses no longer work
Most tenancy agreements written before 1st May 2026 included a clause permitting the landlord to increase rent on an annual basis, typically tied to the Consumer Price Index, a fixed percentage, or the landlord's discretion. These clauses were enforceable under the old system. Under the Renters' Rights Act 2025, they are not.
From 1st May 2026, any contractual term in a residential tenancy agreement that purports to allow a rent increase, other than through the Section 13 procedure, ceases to have effect. It does not matter how clearly the clause is drafted, how long the tenancy has been running, or whether the tenant previously agreed to increases under that clause. The clause is void. Critically, any rent increase that was agreed before 1st May 2026 under a rent review clause, but which was due to take effect after that date, is also not permitted. The transition to the new system is clean and there is no mechanism for a pre-agreed contractual increase to carry over. (Source: Renting out your property: guidance for landlords and letting agents, Rent increases, GOV.UK, November 2025.)
This catches a significant number of self-managing landlords off guard, particularly those who have managed tenancies for several years and have built annual rent reviews into their standard practice. The practical consequence is straightforward: a landlord who sends a letter to a tenant stating that rent is increasing next month because the tenancy agreement permits it has no legal basis for that increase. The tenant can decline to pay the higher amount and the landlord has no valid mechanism to enforce it. The only enforceable route is Section 13.
What is the Section 13 procedure?
Section 13 of the Housing Act 1988, as amended by the Renters' Rights Act 2025, sets out the procedure by which a landlord may propose a rent increase on a periodic assured tenancy. It is the only permitted mechanism for increasing rent on any private residential tenancy in England from 1st May 2026. (Source: Housing Act 1988, section 13, as amended; Guide to the Renters' Rights Act, GOV.UK.)
The procedure requires a landlord to serve a written notice on the tenant proposing a new rent. The notice must be served using the prescribed form, Form 4A, and must satisfy a series of requirements as to its content, the notice period given, and the date from which the proposed rent is to take effect.
The tenant has the right to challenge the proposed rent at the First-tier Tribunal (Property Chamber) if they consider it above the market rate. If no challenge is made, and the notice is valid, the new rent takes effect on the date specified in the notice. GOV.UK guidance also recommends that landlords discuss any proposed increase with the tenant before serving Form 4A, though this is not a legal requirement. (Source: Renting out your property: guidance for landlords and letting agents, Rent increases, GOV.UK.)
What is Form 4A and where does it come from?
Form 4A is the prescribed form for proposing a rent increase under Section 13 on a periodic assured tenancy. It is published by the government and available to download from GOV.UK free of charge on or after 1st May 2026. It replaces Form 4, which applied under the pre-Act rules.
The form cannot be substituted. A landlord who serves a letter, an email, or their own document, even one that contains all the same information, does not satisfy the Section 13 requirement. The notice must be on Form 4A, completed in full. (Source: The Assured Tenancies and Agricultural Occupancies (Forms) (England) Regulations, as amended by the Renters' Rights Act 2025.)
What must Form 4A contain?
A correctly completed Form 4A must include the address of the property to which the tenancy relates, the name of the landlord and the name of the tenant, the existing rent and the proposed new rent, the date on which the new rent is proposed to take effect, and a statement informing the tenant of their right to apply to the First-tier Tribunal if they wish to challenge the proposed rent.
All sections must be completed. A form with blank sections or an incomplete address is defective and cannot be relied upon. Landlords who use a template should check the current version on GOV.UK before serving, as forms are occasionally updated and an outdated version may be invalid.
What notice period is required?
The minimum notice period under Section 13 is two months. This means the date specified in the notice as the date on which the new rent is to take effect must be at least two months after the date on which the notice is served on the tenant. (Source: Housing Act 1988, section 13(2), as amended; Renting out your property: guidance for landlords and letting agents, Rent increases, GOV.UK.)
The two months runs from the date of service, not the date on which the form was written or printed. If a landlord writes the notice on the 1st of April but does not serve it until the 7th of April, the two month period begins on the 7th. This matters when calculating whether the proposed start date is valid.
The proposed start date must also be the first day of a new rental period. If rent is due on the 1st of each month, the new rent can only take effect on a 1st. It cannot take effect mid-period. If rent is due on the 15th, the new rent can only take effect on a 15th. A notice that specifies a date that does not fall on the first day of a rental period is defective. (Source: Housing Act 1988, section 13(3).)
The first year rule: when you cannot increase rent at all
Landlords cannot increase rent during the first year of a tenancy. This applies to all new tenancies created on or after 1st May 2026. A landlord who attempts to serve a Section 13 notice during the first twelve months of a tenancy is acting outside the rules and the notice will have no legal effect regardless of how correctly it has been prepared. (Source: Renting out your property: guidance for landlords and letting agents, Rent increases, GOV.UK.)
This is a significant practical constraint for landlords who let properties at below-market rents initially, or who anticipate needing to adjust rent early in a tenancy. The twelve month clock runs from the start of the tenancy, not from the first rent payment date.
How often can a landlord increase rent?
Under the Renters' Rights Act 2025, a landlord may only increase rent once in any twelve month period. The twelve month restriction runs from the date the last increase took effect, not from the date the previous notice was served. This is an important distinction. If a landlord serves notice in June 2026 and the new rent takes effect from 1st August 2026, the earliest the next increase can take effect is 1st August 2027, not June 2027. (Source: Renting out your property: guidance for landlords and letting agents, Rent increases, GOV.UK.)
This restriction also applies where a previous increase was made under a rent review clause in a tenancy agreement, or where notice was served using the old Form 4 before 1st May 2026. In both cases the twelve months runs from when that earlier increase actually took effect.
How to serve the notice correctly
Form 4A must be served on the tenant in writing. GOV.UK confirms three acceptable methods of service: in person, by post, or by email where email service is permitted under the tenancy agreement. (Source: Renting out your property: guidance for landlords and letting agents, Rent increases, GOV.UK.)
Regardless of the method used, landlords should use a method that generates a reliable record of both delivery and the date of service. First class post to the tenant's address is acceptable but landlords should retain proof of postage, not just a note that a letter was sent. A certificate of posting obtained at a post office or a tracked delivery receipt provides better evidence.
Email is only valid where the tenancy agreement expressly permits notices to be served electronically. Sending to an email address the tenant has used for general correspondence is reasonable practice, but landlords should retain a sent copy and consider requesting a read receipt.
Personal delivery eliminates most service disputes. If using personal delivery, note the date and time on a retained copy and ask the tenant to acknowledge receipt in writing, even informally.
What landlords should not do is serve Form 4A by text message or through a messaging app. These methods are not standard methods of service for legal notices and will not provide reliable evidence of delivery if the matter is later disputed.
What happens if the tenant does not challenge the notice?
If the tenant receives a valid Form 4A and does not apply to the First-tier Tribunal before the proposed start date, the new rent takes effect on the date specified in the notice. No further action is required from the landlord. The tenant is obliged to pay the new rent from that date.
The landlord should update their rent records and any standing order or direct debit arrangements accordingly. A tenant who continues to pay the old rent after the new rent has taken effect is in arrears in the amount of the difference.
What happens if the tenant challenges the notice at the First-tier Tribunal?
A tenant who believes the proposed rent is above the market rate may apply to the First-tier Tribunal (Property Chamber) to have the rent assessed. The application must be made before the date specified in the notice as the date the new rent is to take effect. If the tenant misses that deadline, the right to challenge is lost and the new rent stands. (Source: Housing Act 1988, section 14, as amended by the Renters' Rights Act 2025.)
When a valid application is made in time, the Tribunal will determine the market rent for the property. It will assess what a willing landlord and willing tenant would agree on the open market at the date of the hearing, taking into account the size, condition, location, and comparable lettings in the area. The increase must be in line with the rent a landlord would expect to receive if reletting the property on the open market. (Source: Renting out your property: guidance for landlords and letting agents, Rent increases, GOV.UK.)
Under the new Form 4A regime, the Tribunal cannot determine a rent higher than the amount proposed by the landlord. If the Tribunal considers the market rent to be above the landlord's proposed figure, the determination is still capped at what the landlord asked for. This is a protection introduced by the Renters' Rights Act 2025 that did not exist under the old rules.
It is important to note that this cap applies specifically to notices served under Form 4A on or after 1st May 2026. For notices served under the old Form 4 before that date, the transitional rules are different. The Tribunal retains the ability to determine a rent that is the same, higher, or lower than what was proposed, and the new rent takes effect from the date specified in the original notice. (Source: Renting out your property: guidance for landlords and letting agents, Rent increases, GOV.UK.)
Where a Tribunal determines the rent under the new Form 4A regime, the increase takes effect from the date of the Tribunal's determination, not the date specified in the notice. This means increases are not backdated where a tenant has exercised their right to challenge.
In practice the vast majority of tenants do not apply to the Tribunal. The process exists as a safeguard against above-market increases, not as a routine obstacle. Landlords who propose rents genuinely in line with local comparable lettings are unlikely to face a challenge.
What level of increase is defensible at Tribunal?
The Tribunal determines market rent by reference to comparable lettings in the same area. A landlord whose proposed rent is broadly in line with what similar properties are currently being advertised for in the same postcode is in a strong position. A proposed rent significantly above current local market levels is vulnerable to being reduced.
Landlords uncertain about the local market rate before serving Form 4A should check current listings for comparable properties in the same street or immediate area. The relevant measure is the current asking rent for similar properties, not the rent those properties were let at several years ago. Rightmove and Zoopla both provide current letting market data that landlords can use as a reference.
Landlords do not need to justify the proposed rent in the notice itself. The justification only becomes necessary if the tenant applies to the Tribunal, at which point the landlord will need to produce comparables to support their figure.
Common mistakes landlords are making
The most widespread mistake is continuing to rely on contractual rent review clauses after 1st May 2026. Some landlords, and some letting agents managing properties on their behalf, continue to send annual rent review letters referencing the tenancy agreement rather than serving Form 4A. Those letters have no legal effect. The tenant is under no obligation to pay the higher amount.
The second most common mistake is assuming that a pre-agreed contractual increase carries over into the new regime. It does not. Any increase agreed under a rent review clause but taking effect after 1st May 2026 is not permitted regardless of when it was agreed.
The third mistake is calculating the notice period from the date the form was written rather than the date it was served. A notice written on the 28th of April and posted on the 3rd of May must run two months from the 3rd of May. A landlord who serves on the 3rd of May specifying a start date of 1st July has given insufficient notice. The two months does not expire until the 3rd of July, and the next valid rental period start after that would be 1st August if rent is monthly.
The fourth is specifying a proposed start date that does not fall on the first day of a rental period. This defect invalidates the notice regardless of how well it is otherwise prepared.
The fifth is using an outdated version of Form 4A. The current version should be downloaded from GOV.UK immediately before serving, not from a folder of documents saved months earlier.
The sixth is attempting to increase rent during the first year of a tenancy. This is not permitted under any circumstances and a notice served in the first twelve months has no legal effect.
The seventh is serving by text message or informal digital message with no reliable record of delivery.
What this means in practice
For the majority of self-managing landlords with straightforward periodic tenancies, the Section 13 process is not complex once understood. The practical steps are: wait until the tenancy is at least twelve months old; download the current Form 4A from GOV.UK; complete it in full with the correct proposed rent and a start date that is at least two months from the date of service and falls on the first day of a rental period; serve it by an approved method that generates a delivery record; retain a copy of the completed form and the evidence of service; and wait. If no Tribunal application is made before the start date, the new rent takes effect automatically.
The critical shift from the old system is that the paperwork now matters in a way that a contractual clause never required. Under the old system a rent review clause was self-executing. Under the new system the legal basis is the correctly served Form 4A, and a landlord who cannot produce that form and evidence of its service has no enforceable increase.
LLCR tracks rent review eligibility dates across a portfolio and reminds landlords when they are next able to serve a Section 13 notice. Landlords can run a free compliance check at llcr.uk/compliance-checker.html, no login or sign-up required.
Sources: Housing Act 1988, section 13 and section 14, as amended by the Renters' Rights Act 2025; Renters' Rights Act 2025; Guide to the Renters' Rights Act, GOV.UK, November 2025; Renting out your property: guidance for landlords and letting agents, Rent increases, GOV.UK, November 2025; The Assured Tenancies and Agricultural Occupancies (Forms) (England) Regulations, as amended.
This article is for informational purposes only and does not constitute legal advice. For advice specific to your circumstances, consult a qualified solicitor.