Section 13 Rent Increases: The Eight Ways a Form 4A Fails (and How to Serve One That Doesn't)
The Section 13 rent increase notice after the Renters' Rights Act: the eight ways a Form 4A fails, a worked example for the start date, and what a tribunal challenge really means. England only.
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Since 1 May 2026 there is exactly one lawful way to raise the rent on a private assured tenancy in England: a Section 13 notice on Form 4A, served complete, with at least two months’ notice, no more than once a year (strictly every 52 weeks, sometimes 53). Rent-review clauses in your old agreement are dead, and there is no “we just agreed it” route. The notices that go wrong go wrong on details: a date one day off the tenancy period, a page left off, a premature serve. This guide is organised around those failures, because that is where the money is lost. It assumes you have read our main Renters’ Rights Act audit; this is the rent chapter in full.
Rent rises on a private tenancy now go through Form 4A only: all nine pages, at least two months’ notice, once every 52 weeks (sometimes 53), starting on the first day of a tenancy period. Old rent-review clauses are dead and “we agreed it” is not a route. At tribunal, your proposed figure is a ceiling. The eight failure modes and the date maths are below.
Why is Form 4A now the only route?
The Act rewrote Section 13 of the Housing Act 1988. The new subsection 13(4A) says rent for a period may not be greater than the previous period’s rent except through a Section 13 notice (or what follows one: agreement at or below the proposal, or a tribunal determination). Any term of your tenancy that says otherwise “is of no effect” (RRA 2025, s.6; HA 1988 s.13 as amended). GOV.UK’s plain-English version: “Rent increases by any other means – such as rent review clauses – will not be permitted” (guide to the RRA).
Note what is missing from that list: a mutual-agreement route. The Act leaves no provision for a private tenancy rent rise by bare agreement without a notice; what a tenant voluntarily pays on a handshake is legally untested, and the safe position is that an increase outside Section 13 is not lawfully due. Even a happy tenant gets a Form 4A.
The form itself replaced Form 4 for private landlords on 1 May 2026. Form 4 still exists for social housing, which is exactly why using an old template is failure number one (GOV.UK forms page, updated 1 May 2026).
The eight ways a Form 4A fails
| # | The mistake | The consequence | The fix |
|---|---|---|---|
| 1 | Using old Form 4 or a pre-May template | Wrong prescribed form for a private tenancy | Download Form 4A fresh from GOV.UK each time |
| 2 | Leaving pages off (usually Section 5, the tenant’s rights) | A prescribed form served incomplete risks the whole notice | Serve all 9 pages as published |
| 3 | Start date not the first day of a tenancy period | Invalid on the case law; assume no rescue | Anchor the date to the day your periods start |
| 4 | Less than two months between service and start date | The form itself tells the tenant this is challengeable | Count from the date of service, leave margin |
| 5 | Serving inside the 52/53-week clock | Notice premature | Check the dates in Q4.3/Q4.4 before choosing the date |
| 6 | Relying on the old rent-review clause | Of no effect; the increase is not lawfully due | Serve Form 4A instead |
| 7 | “We agreed it over text”, no notice | No agreement route exists for private tenancies | Put it through Form 4A even when the tenant is happy |
| 8 | No proof of service | Nothing to show if validity is challenged | Use your agreement’s service method, or hand / leave at the address / registered post, and keep evidence |
Rows 1, 2 and 6 to 8 are self-explanatory with their fixes. Rows 3 to 5 are the date maths, which deserves its own section.
How do you get the start date right?
Three requirements run at once, all from the form’s own notes and the statute (Form 4A, Note A; HA 1988 s.13(2)):
- Two months. The new rent cannot start earlier than two months after the date of service.
- The 52/53-week clock. No increase until 52 weeks after the last one (or after the tenancy began, for a first increase). It stretches to 53 weeks where the new date would land more than 6 days before the anniversary of the date in Q4.4; that anti-drift rule exists because 52 weeks is slightly short of a calendar year. Quote the form’s own wording if in doubt; do not improvise the test.
- The tenancy period. The new rent must start on the first day of a period. The form’s example: monthly tenancy starting on the 20th, new rent starts on a 20th. Weekly tenancy started on a Monday, new rent starts on a Monday. A “period” follows how often rent is paid, and must be a month or less.
Worked example. Monthly tenancy, periods run the 20th to the 19th. Last increase took effect 20 September 2025. You hand the notice to your tenant on 11 August 2026. Two months from service is 11 October 2026, but that is mid-period, so the earliest valid start is the next period start: 20 October 2026. The 52-week clock from 20 September 2025 ran out on 19 September 2026, so it is no bar. Q4.6 reads 20 October 2026. Writing 11 October, exactly two months, would fail requirement 3, and that is precisely the failure the Court of Appeal has already ruled on.
What happens if the date is wrong?
The leading case is Mooney v Whiteland [2023] EWCA Civ 67: a weekly tenancy running Monday to Sunday, and a notice specifying a Friday. The Court of Appeal held the notice invalid, and it could not be saved by the reasonable-recipient principle (case summary, Trinity Chambers). That case pre-dates the Act, but it was decided on the same “beginning of a new period” wording that survives in today’s Section 13.
Neither the amended statute nor GOV.UK offers any saving provision for a wrong-dated notice, and no tribunal decisions under the new regime exist yet. The safest assumption is the blunt one: a wrong date means you start again, two months and all.
New since May: the tribunal itself can now rule on whether a Section 13 notice is valid (new s.13B), and validity and rent level are separate applications (RRA 2025, s.6; GOV.UK tribunal application page). Your notice’s defects now have a cheap, dedicated venue.
What does a tenant challenge actually mean for you?
Your tenant can apply to the First-tier Tribunal to challenge the proposed rent, using form MR1 with a £47 fee, any time before the start date in your notice (GOV.UK tribunal application page, page updated 10 August 2026; HA 1988 s.13(4)). Three consequences worth knowing before you pick your number:
- Your proposal is now a ceiling. The tribunal determines the open-market rent, and the rent payable is the lower of that and your proposed figure (s.14ZB(5)). The tribunal may find the market rent is higher than you asked; the tenant still cannot be required to pay more than your notice proposed (RRA 2025, s.7). Pricing timidly to seem reasonable no longer buys you anything at the tribunal; pricing at your honest market figure costs the tenant nothing extra either way.
- There is no backdating. If the determination lands after your notice’s start date, the new rent runs from the first tenancy period beginning on or after the determination (the tribunal can defer it further for undue hardship, by up to two months from the determination). The old rent applies until then, and those months are never recovered. If the determination lands before your start date, your notice’s date holds.
- The increase freezes while the challenge runs. The form tells tenants directly that the new rent is not payable until the tribunal decides.
The cap binds what the tenant pays, not what the tribunal thinks. Price at your honest market figure: it cannot cost the tenant more than your notice proposed, and undershooting buys you nothing.
The tribunal assesses what the property would let for on the open market on the same terms, and can consider its condition; evidence from actual market lettings counts for more than housing-association or local-housing-allowance figures (GOV.UK).
FAQ
Do I really have to serve all nine pages? Yes. It is a prescribed form; serve it as published. Landlords in one forum thread openly discussed leaving off Section 5 so as not to put ideas in tenants’ heads. An incomplete prescribed form risks the whole notice, and Section 5 is also where the form does your explaining for you.
Whose signature goes on page 9? Nobody’s, usually. Page 9 is the extra-sheets continuation page; its signature line is for you, only if you used extra sheets. There is no tenant acceptance signature anywhere on Form 4A; the tenant does not have to agree, sign or reply for the notice to work.
Can we skip the form if the tenant agrees to the increase? No. There is no agreement route for private tenancies outside Section 13. Serve the form; the tenant agreeing simply means no challenge comes.
Once a year or 52 weeks? GOV.UK says once per year; the statute runs a 52-week clock, stretching to 53 in the anti-drift case. Practical test: has there been an increase in the last 53 weeks? If yes, wait.
Can the tribunal put the rent up beyond what I asked? It can find the market rent is higher, but the payable rent is capped at your proposal. The cap binds what the tenant pays, not what the tribunal thinks.
Where to go deeper
Form 4A itself contains unusually good notes; read them once before your first serve. The Independent Landlord’s Section 13 guide is the strongest completion-led walkthrough if you want a second angle. For everything else the Act changed, start with the landlord audit; the Information Sheet fix and the rest of the landlord guides live on the hub.
Homesful guides are general information for landlords in England, not legal advice. For a specific dispute, penalty or possession issue, speak to a solicitor or a landlord association advice line. Every claim above links to its source; guidance current as of 11 August 2026 (Form 4A and the forms page current at 1 May 2026; the market-rent-determination page updated 10 August 2026).