Under the old system, many landlords could raise rent however often their tenancy agreement allowed, with limited formal process. The Renters' Rights Act tightens this considerably — and the old rent-review clause in your existing agreement may no longer be the mechanism you think it is.
The Process Itself: Section 13 and Form 4A
For assured periodic tenancies under the new regime, landlords use the revised section 13 process. Rent may normally be increased only once a year, the proposed increase must be notified using the current Form 4A, and at least two months' notice must be given. A first increase cannot take effect during the first 12 months of a new tenancy. Do not assume an old rent-review clause can be used for a new increase after 1 May 2026 — that assumption is one of the clearer ways landlords get caught out by the transition.
Building a Defensible Rent Increase
Before serving anything, assess open-market rent using genuinely defensible comparable evidence — dated comparables with your reasoning recorded, not a round-number guess. A tenant can challenge a proposed rent above open-market rent at the First-tier Tribunal, so the evidence you gather before serving Form 4A is also the evidence you would need if the increase is disputed afterward. Check the tenancy start date and the effective date of any previous increase before proceeding, since both timing restrictions — the 12-month floor on a new tenancy and the once-a-year cap generally — need to be satisfied together, not just one or the other.
What a Compliant Increase Actually Looks Like, Step by Step
Confirm the tenancy sits within the section 13 regime, check both relevant dates, assess and document open-market rent with real comparables, complete the current Form 4A checked immediately before service since the form itself can be updated, set a lawful effective date allowing at least two months' notice, and retain evidence of how and when you served it. If a challenge follows, your valuation evidence and communications are what you will rely on at tribunal.
Where to Go From Here
The Complete Renters' Rights Act 2025 Compliance Blueprint includes the full rent increase decision checklist and a rent review evidence worksheet, alongside the complete tenancy audit, possession framework, and every other operational change the Act introduces.
Get The Renters' Rights Act 2025 Compliance Blueprint →
This article is for educational and informational purposes only and does not constitute legal advice. Confirm the current Form 4A and official guidance directly on GOV.UK before serving a rent increase notice.