Landlord raising your rent? They must use Form 4A — or it’s not valid.

From 1 May 2026, the only lawful way for a landlord to increase your rent is to serve a Section 13 notice on Form 4A, giving at least 2 months’ advance notice. An informal email, a verbal request, or a letter that does not use the prescribed form is not a valid rent increase — you do not have to pay it.

Form 4A Rent Increase Notice

New rules from 1 May 2026

Landlord raising your rent?

They must use Form 4A — or it’s not valid.

From 1 May 2026, the only lawful way for a landlord to increase your rent is to serve a Section 13 notice on Form 4A, giving at least 2 months’ advance notice. An informal email, a verbal request, or a letter that does not use the prescribed form is not a valid rent increase — you do not have to pay it.

And even if the form is correct, your landlord can only increase your rent once every 12 months. If you think the proposed amount is above market rate, you can challenge it at the First-tier Tribunal.

What makes a rent increase valid.

Under the Renters’ Rights Act 2025, a rent increase is only valid if all of the following are true. Use this as a checklist when you receive a notice from your landlord.

Landlord hasn’t used Form 4A?

Do not simply pay the new amount — it may set a precedent. Write to your landlord explaining that a valid Form 4A with 2 months’ notice is required. If they then serve a valid notice, your challenge window restarts from that date.

Think the increase is too high? Apply to the tribunal.

If your landlord has served a valid Form 4A but you believe the proposed rent is above the open market rate for comparable properties in your area, you can apply to the First-tier Tribunal (Property Chamber). The tribunal will independently assess the market rent and set it accordingly.

Apply before the increase date

You must apply to the tribunal before the date the rent increase is due to take effect. Once it has taken effect, you lose the right to challenge the amount (though you can still challenge whether the Form 4A was valid).

Gather comparable evidence

The tribunal will look at what similar properties in your area are renting for. Collect listings from Rightmove, Zoopla, or OnTheMarket for comparable properties — size, location, condition. This is your strongest evidence.

Tribunal hearings for rent increases are usually in person. You can represent yourself. Start My Claim prepares your written submissions and evidence bundle so you arrive ready.

Tribunal sets the market rent

The tribunal can only set the rent at the open market rate — not below it. But if your landlord is asking for above market, the tribunal will cap it. The new rate is binding on both you and your landlord.

What you can do when you receive a Form 4A.

If you are happy with the new amount, simply pay it when it falls due. You do not need to do anything.

Contact your landlord and propose a lower figure. If you agree, confirm the agreed amount in writing to avoid any dispute later.

Apply to the First-tier Tribunal before the increase date. Start My Claim prepares your application and evidence bundle.

Challenge an above-market rent increase.

Start My Claim checks your Form 4A notice for validity, assesses whether the proposed rent is above market, and prepares your First-tier Tribunal application. Fixed fee £67.

Form 4A rent increase — FAQ

Sources: Housing Act 1988, s.13 (as amended by the Renters’ Rights Act 2025) · Renters’ Rights Act 2025 (c.34), s.7 (rent increase procedure) · MHCLG: The Renters’ Rights Act Information Sheet 2026 · First-tier Tribunal (Property Chamber) Rules 2013