Form 4A explained: the new rent increase notice landlords must use from 1 May 2026

From 1 May 2026, your landlord can't use the old Section 13 rent increase form. The Renters' Rights Act 2025 replaces the existing Form 4 with a new prescribed form — Form 4A — and if your landlord serves you on the old form on or after that date, the notice is invalid.

For renters, this is a quiet but important change. Every Section 13 rent increase in England after 1 May 2026 has to be on Form 4A. That gives you a clean, binary first check: right form, or wrong form? If wrong, you don't have to pay the new rent, full stop.

This post explains what Form 4A is, what's changed since Form 4, and what to do in the first 72 hours after one lands on your doormat.

What is Form 4A?

Form 4A is the prescribed notice under Section 13 of the Housing Act 1988, as amended by the Renters' Rights Act 2025. It replaces the old prescribed Form 4 for all new rent increase notices served from 1 May 2026 onwards.

"Prescribed" is the key word. The law says there's only one form landlords can use for a statutory rent increase, and that form is the government-approved version. A landlord can't write their own version, scribble the same information on the back of an envelope, or use an older version of the form. If they do, the notice fails at the first hurdle.

In practical terms, Form 4A is the document that:

• Tells you your landlord wants to raise the rent.
• States the new proposed rent.
• Sets out the date the new rent would take effect from.
• Tells you how to challenge it if you don't agree.

What changed from Form 4 to Form 4A

The form looks similar on the surface. The important changes sit in the legal rules behind it.

Item	Form 4 (pre-1 May 2026)	Form 4A (from 1 May 2026)
Minimum notice period	1 month (weekly/monthly), up to 6 months (yearly)	2 months, regardless of tenancy type
Effective date	Must align to a period of the tenancy	Must align, and must respect the 2-month minimum
Tribunal risk to tenant	Tribunal could set rent higher than landlord proposed	Tribunal cannot set rent higher than landlord proposed
Backdating	Tribunal decision backdated to notice expiry date	No backdating — new rent takes effect from the decision date
52-week rule between increases	Yes	Yes (unchanged)
Must use the prescribed form	Yes (Form 4)	Yes (Form 4A)

Two of those changes are significant for you.

The tribunal risk change is the most important. Under the old rules, a tenant who applied to the First-tier Tribunal to challenge a rent increase ran a real risk — if the tribunal looked at local market evidence and decided the landlord's figure was conservative, it could set the rent higher. That kept a lot of tenants with valid grounds from challenging at all. From 1 May 2026, the tribunal can only reduce or confirm the proposed rent. It can't go higher. The downside disappears.

The no-backdating change is the second. Under Form 4, a tenant who challenged and lost would often owe months of back-rent — the new figure applied from the date on the original notice, not the date of the tribunal decision. Under Form 4A, the new rent only applies from the decision date. The waiting time is yours, not theirs.

What a valid Form 4A notice must contain

We'll describe the categories the notice must cover, rather than the exact wording — the regulations setting out the precise layout were still being finalised as the Act came into force, and the safest thing a tenant can do is use the procedural check built into a tool like RentSOS rather than second-guess the printed version.

A valid Form 4A notice must include:

1. Identification — your name(s) as tenant, the landlord's name, and the full property address.
2. The proposed new rent — the exact amount, stated clearly (e.g. "£1,450 per calendar month"), not a percentage or range.
3. The start date of the new rent — must be at least 2 months after the notice is served, and must align with a "day of the period of the tenancy" (for a monthly tenancy, the rent-payment anniversary).
4. The basis for the increase — reference to Section 13 of the Housing Act 1988 as the authority.
5. Information about your right to apply to the tribunal — how, and by when.
6. Signature and date — the landlord's signature (or their letting agent's, if they have authority), and the date of service.

If any of those elements is missing, wrong, or internally inconsistent (e.g., the date the rent takes effect is less than 2 months from the notice date), the notice is invalid. An invalid notice means the new rent doesn't take effect — you keep paying the old rent.

[!info] What "service" means Form 4A is "served" when it reaches you. This is usually the date it arrives at the property (post), the date it's handed to you (in person), or the date of an agreed email (if your tenancy agreement allows electronic service). Date-stamp the envelope when it arrives — that's the clock starting.

What to do in the first 72 hours

You've received what looks like a Form 4A. Don't panic and don't agree to anything yet. Three things to do:

Hour 1: read it carefully

Read the whole form. Not just the new rent figure — all of it. Look for the proposed start date, the landlord's signature, the property address (is it exactly right?), and whether Section 13 / Renters' Rights Act 2025 is named as the legal basis.

Hour 2: date everything

Note down:

• The date you received the notice.
• The start date the landlord has proposed for the new rent.
• The gap between the two — this must be at least 2 months.
• The date of the last rent increase (if any). If it's less than 52 weeks ago, the notice is invalid on that ground alone.

Hour 3: decide which bucket you're in

There are three possible outcomes:

1. The notice is invalid. You do nothing — the old rent continues. (Still, reply to your landlord in writing explaining why the notice is invalid, so you have a paper trail.)
2. The notice is valid and the new rent looks fair. Consider whether to accept it or to negotiate a middle figure directly. You don't have to accept a figure just because it's lawful.
3. The notice is valid but the new rent is above the local market rate. You have a choice: accept, negotiate, or challenge at the First-tier Tribunal. Because Form 4A removes the risk of a higher tribunal-set rent, challenging is materially safer than it was before 1 May 2026.

Within 24 hours: get an objective check

RentSOS checks procedural validity in about two minutes, benchmarks the rent against local market data, and tells you which of the three buckets you're in — free until you have grounds to challenge. If grounds are found, the £14.99 pack includes the negotiation letter and the tribunal template.

Common mistakes landlords will make in the first six months of Form 4A

New forms always generate early errors. From our experience of Form 4 notices under the old rules, these are the patterns to watch for in Form 4A:

• Using the old Form 4 by habit. Letting agents who haven't updated their template will serve the wrong form.
• 1-month notice period. Habit again — the old minimum was one month for monthly tenancies. From 1 May 2026, it's two.
• Start date less than 2 months from service. Easy arithmetic error, especially around month-end.
• Serving within 52 weeks of the last increase. The 52-week rule didn't change.
• Unsigned notices, or ones signed by someone without authority.
• Wrong tenant name(s). If you're in a joint tenancy, every named tenant must be addressed.
• Addressing the property informally (e.g., "Flat 3" instead of the full address on the tenancy agreement).

None of these make the landlord a villain. Many are genuine mistakes, especially in the first few months of the new regime. But a mistake is still a mistake — and it still makes the notice invalid.

If you were served before 1 May 2026

The rules that apply are the rules when the notice was served, not the rules on the day the new rent is due to start. If your landlord served you on 20 April 2026 with a new rent starting 20 May 2026, that's a Form 4 notice under the old rules — including the old tribunal risks.

For notices served before 1 May 2026, read our Section 13 Form 4 guide for tenants. For an overview of what the Renters' Rights Act 2025 changes, see what changes from 1 May 2026.

If you're not sure what you've been served with

Run the notice through RentSOS. It's free, it's specific to England, and it's built to spot both Form 4 and Form 4A errors. If grounds are found, the paid pack gives you the documents you need to act — a negotiation letter and, where appropriate, a tribunal application template.

FAQs

Q: My landlord used Form 4 instead of Form 4A after 1 May 2026. What happens? A: The notice is invalid. The new rent doesn't take effect, and you continue paying the old rent. Reply in writing (email is fine) saying you don't accept the notice because it's on the wrong form. Keep a copy.

Q: Can my landlord just reissue with Form 4A? A: Yes. They can withdraw the invalid notice and serve a fresh Form 4A, provided the usual rules (2-month notice, 52-week gap from the last increase) are met.

Q: The form looks right but the figure is above market rate. Is the notice still valid? A: Probably yes on procedure, but the amount can be challenged at the First-tier Tribunal. From 1 May 2026, the tribunal can't set the rent higher than the landlord proposed, so there's no downside to applying.

Q: What if I just don't pay the new rent? A: If the notice is valid and you don't challenge at the tribunal before the effective date, the new rent starts legally. Not paying at that point can lead to rent arrears and, in serious cases, eviction proceedings. Challenging is the safe way to disagree.

Q: Does Form 4A apply to assured tenancies, assured shorthold tenancies, or both? A: From 1 May 2026, the Renters' Rights Act 2025 converts existing assured shorthold tenancies to assured tenancies, and Section 13 + Form 4A is the only permitted route for rent increases on those tenancies. So it applies to both, but from 1 May they're effectively the same thing.

Key takeaways

• Form 4A is the prescribed notice landlords must use for rent increases in England from 1 May 2026.
• The minimum notice period is 2 months, up from 1 month under Form 4.
• The tribunal cannot set the rent higher than the landlord proposed, which removes the main risk of challenging.
• Decisions made by the tribunal from 1 May 2026 are not backdated to the notice date.
• Always check the form for procedural validity first — if the notice is invalid, you don't pay the new rent.