Form 3 and Rent Increases: Getting the Right Form

What changed under the Renters’ Rights Act 2025

Section 21 abolished. Fixed-term assured tenancies abolished. Ground 8 threshold raised to 3 months. Information Sheet required for every tenancy by 31 May 2026. Read the full guide.

If you have been told to serve "Form 3" to increase the rent on an assured tenancy, stop: in England, Form 3 was never the rent increase form. Form 3 was the prescribed Section 8 notice seeking possession from 1989 until the Renters' Rights Act 2025 reforms. The prescribed form for a private section 13 rent increase is now Form 4A — and before 1 May 2026 it was Form 4. Some older guides and template packs mislabel these forms, which is where the confusion comes from.

Form 3 — what it actually was

Form 3 was the form a landlord used to tell a tenant that possession proceedings were coming — the notice under section 8 of the Housing Act 1988. It was prescribed as Form No. 3 by the original 1988 Forms Regulations (SI 1988/2203), and it kept that number through the 1997 Regulations (SI 1997/194) and the 2015 Regulations. From 1 May 2026, private landlords use Form 3A for a notice of possession proceedings instead; Form 3 remains only for social-housing assured tenancies.

The rent increase form: Form 5, then Form 4, now Form 4A

The section 13(2) notice proposing a new rent has had three prescribed forms in England:

• Form No. 5 under the 1988 Regulations (SI 1988/2203) — the original numbering.

• Form No. 4 from the 1997 Regulations onwards — the number most landlords knew it by for nearly three decades.

• Form 4A from 1 May 2026 for the private rented sector (SI 2026/354). GOV.UK is explicit on the old form: "Do not use this form if the property is rented privately. You should use form 4A." Form 4 remains in use only for social-housing assured tenancies.

The relevant prescribed form for a rent increase on a private assured periodic tenancy today is Form 4A. See our Form 4A page for the full procedure.

What if I served a rent increase notice on an old form?

A section 13 notice served before 1 May 2026 on the then-prescribed Form 4 is preserved by the transitional provisions in the 2026 Regulations — the notice and its proposed rent still stand even if the new rent starts after that date.

A notice served on or after 1 May 2026 on the wrong form (old Form 4, or anything labelled "Form 3") is not a valid section 13 notice for a private tenancy. The conservative course is to serve a fresh Form 4A — the notice period runs from service of the new notice, not the original.

What if I served a contractual rent review under my old AST?

Contractual rent review clauses in pre-RRA agreements are of no effect from 1 May 2026. A review carried out before that date and effective before that date is generally valid. A review purporting to take effect on or after 1 May 2026 cannot rely on the contractual clause and must use Form 4A.

Related guidance

• Form 4A — the form you need now

• Rent increases — full procedural guide

• Renters’ Rights Act 2025 — full guide