Form 4A Rent Increases after 1 May 2026: the plain-English guide for landlords in England

What changed on 1 May 2026?

From 1 May 2026, rent increases for assured periodic tenancies in England moved fully onto the section 13 / Form 4A route.

In practical terms, this means:

• You must use the official Form 4A
• You must give at least two months’ notice
• You cannot increase rent during the first 12 months of the tenancy
• You cannot increase rent more than once in any 12-month period
• Tenants can challenge the proposed figure at tribunal if they believe it is above market rent

A legally valid notice can still result in the tribunal setting a lower rent if the evidence does not support the figure proposed and even if upheld, going to tribunal will delay the implementation of any rent increase.

Who must use Form 4A?

Form 4A is used for:

• privately rented properties
• in England
• where the tenancy is an assured periodic tenancy

If the tenancy is still within a fixed term, stop before serving notice and check the correct route first.

This guide is written specifically for landlords in England. Scotland, Wales and Northern Ireland all use different systems and different rules.

What is Form 4A actually doing?

Form 4A is not a negotiation letter.

It is the official legal notice proposing a new rent under section 13 of the Housing Act 1988.

The form itself does not guarantee the increase will stand if challenged. Instead, it formally starts the process and gives the tenant the opportunity to:

• accept the increase,
• negotiate,
• or apply to the tribunal for an open-market-rent determination.

The safest workflow before serving notice

The biggest mistake landlords make is filling in the form first and scrambling for evidence later.

The safer approach is:

The fields landlords most commonly get wrong

What happens if the tenant challenges the increase?

Tenants can apply to the tribunal before the proposed increase date if they believe the new figure exceeds the open-market rent.

The tribunal does not simply ask whether the landlord completed the form correctly, It also asks “What is the market rent for this property?”.

That means evidence matters.

Recent tribunal decisions show that tribunals often consider the following when determining fair market rent:

• local comparables,
• property condition,
• dated décor,
• tenant-funded improvements,
• disrepair,
• furnishing level,
• and how comparable the evidence actually is.

Simply printing Rightmove listings is often weaker than landlords expect.

Why “asking rent” is not always “market rent”

One of the biggest mistakes landlords make in 2026 is assuming:

“The flat down the road is advertised at £X, so mine must be worth the same.”

That is not always how tribunals assess value.

Recent decisions have shown tribunals discounting:

• stale listings,
• unrealistic asking rents,
• broad postcode comparisons,
• and poor-quality evidence.

In a more balanced rental market, accuracy matters more than optimism.

This is exactly why RentShift offers optional human market-rent support.

Form 4A checklist before serving

Before serving the notice, confirm:

• The tenancy is an assured periodic tenancy in England
• The tenancy is outside the first 12 months
• At least 12 months have passed since the last increase
• The tenant receives at least two months’ notice
• The new date aligns correctly with the tenancy period
• The official Form 4A has been used
• The wording has not been altered
• The form has been signed and dated
• You can prove service of the notice with evidence
• You have evidence supporting the proposed figure

Evidence checklist if the rent is challenged

Before serving notice, create one clean evidence file containing:

• tenancy agreement
• tenancy start date
• current rent
• previous increase dates
• comparable local rentals
• recent agreed lettings if available
• property photos
• room sizes
• notes on condition
• details of included charges
• notes on improvements
• proof of service

Tribunals often decide cases largely on the paperwork submitted.

Good preparation reduces risk.

Common landlord mistakes after 1 May 2026

The most common avoidable mistakes are:

• using the wrong form
• using old wording
• serving notice during a fixed term
• miscalculating dates
• giving insufficient notice
• failing to sign the notice
• relying on weak comparables
• proposing unrealistic increases
• failing to keep proof of service