The fee to challenge a rent increase at the First-tier Tribunal in England is £47, and under the fees order debated in Parliament on 27 April 2026 there is no hearing fee on top. The tribunal cannot set your rent above the figure your landlord asked for, and the new rent cannot be backdated to the date on the notice. Run those three facts together and the arithmetic is blunt: if the process takes ten weeks and your landlord wanted another £150 a month, the delay alone is worth roughly £345, against a £47 outlay you cannot lose more than.
That is the change. Before 1 May 2026 a tenant who challenged could end up with a rent higher than the landlord had proposed, which is why almost nobody did it.
What the 1 May 2026 rules changed
Since Phase 1 of the Renters' Rights Act 2025 commenced on 1 May 2026, a Section 13 notice on the prescribed Form 4A is the only lawful way to raise the rent on a private assured periodic tenancy in England. Rent review clauses, fixed-term renewal uplifts and informal "we're putting it up in April" emails have no legal effect. If your tenancy agreement contains a rent escalator, it is now dead paper, whatever the letting agent tells you. Worth re-reading your contract with that in mind: our guide to what to look for in a tenancy agreement covers the clauses that survived the Act and the ones that did not.
Three other rules follow from the same commencement date:
- The notice must give at least two months before the new rent takes effect, measured from service, not from the date the landlord filled the form in.
- Rent can rise only once in any 12 months, and the clock runs from the date the current rent was last set, not from the date of the last notice.
- Form 4 is now for social housing assured tenancies. A private landlord who serves Form 4 after 1 May 2026 has almost certainly served nothing at all.
Check the notice before anything else
Form 4A is a prescribed form under section 13(2) of the Housing Act 1988 as amended. It must be served as published, including the section that tells you how to apply to the tribunal. Landlord-side guidance is unanimous that stripping pages out or retyping it risks invalidity.
Work through this list the day the notice arrives:
| Check | What makes it fail |
|---|---|
| The form itself | Old Form 4, a solicitor's letter, an email in the agent's house style |
| Notice period | Fewer than two months between service and the new rent's start date |
| Start date | Not the first day of a rental period |
| 12-month gap | Less than a year since the rent was last changed or set by a tribunal |
| Service method | Emailed without your prior written agreement to accept notices by email |
| Completeness | Missing pages, missing tribunal information, blank landlord details |
The email point catches a surprising number of agents. Service by email is valid only if you agreed in writing, before the notice was sent, that you would accept notices that way. A clause in the tenancy agreement does the job. A friendly WhatsApp thread does not.
For posted notices, first class is deemed served on the second working day after posting and second class on the fourth. That matters when the two-month period is tight, and the deemed dates are presumptions you can rebut with evidence.
If the notice is invalid, say so in writing and keep paying the existing rent. An invalid notice has no effect, and the landlord has to start again with a fresh Form 4A and a fresh two months. You can also raise validity with the tribunal, which now has an explicit power to consider it.
The deadline: apply before the new rent starts
There is one hard deadline and it is not generous. Your application must reach the First-tier Tribunal (Property Chamber) before the date the proposed rent is due to take effect. Miss it by a day and the increase simply happens.
The application is the RENTS1 form, submitted through the GOV.UK portal. Online submission confirms receipt instantly, which removes the risk of arguing about postmarks later. Postal applications go to the Property Chamber's Market Rents office in Leicester, and if you post it you should assume several days in transit.
A realistic sequence for a monthly tenancy where the notice arrives on 1 September proposing a new rent from 1 November:
- Week one. Run the validity checks. Photograph the envelope and the form.
- Weeks one to three. Gather comparables and write your case.
- By mid-October at the latest. Submit RENTS1 and pay the £47. Do not leave it to the final week.
- 1 November onwards. Keep paying the old rent. Do not amend your standing order.
- Six to twelve weeks after submission. Written determination arrives, based in most cases on paper evidence alone, though the tribunal can call a hearing or inspect.
That six to twelve week range comes from practitioner guidance rather than published statistics, and London backlogs have been the subject of some nervous commentary since May. Longer is better for you, given that the increase cannot be backdated.
Building your evidence
The tribunal is answering one question: what would this flat let for today, on the open market, freshly advertised? Not what the landlord needs to cover the mortgage, not what they spent on the boiler. Improvement costs are not a justification the tribunal weighs on their own.
Start with the ONS Price Index of Private Rents, which is the official series and the one to cite. The July 2026 bulletin puts annual private rent inflation in London at 2.2% in the 12 months to June 2026, the lowest of any English region, against 3.4% for England as a whole and 3.3% across the UK. If your landlord has proposed 8%, the gap between that and the official London figure is the spine of your case. ONS data for the same period put the average London rent at £2,302 a month, with Kensington and Chelsea the most expensive local area in the country at £3,596.
The ONS also publishes borough-level averages and breakdowns by property type and bedroom count. In the May 2026 release, the UK average for flats and maisonettes was £1,351 and for one-bedroom homes £1,123. Pull your own borough's figure and the relevant bedroom count rather than the London-wide average, which is dragged upwards by the central boroughs.
Then do the unglamorous part. Screenshot five to ten current listings for genuinely comparable flats: same borough, similar size and condition, similar walk to the same station. Note the date, the asking rent and the address. A one-bedroom flat five minutes from Brixton on the Victoria line is not comparable to one twenty minutes' walk away in the same postcode, and the tribunal knows the difference.
Photograph what is wrong with your flat: single glazing, damp in the bathroom, the broken extractor the agent has ignored since February, the boiler that takes four minutes to run hot. Condition is part of market rent. So is anything you have paid for yourself.
If your search for comparables suggests the whole borough has moved against you, it may be worth looking at where rents have actually fallen. We track that in our piece on newly subsidised and reduced flats in London.
The tribunal can move the date, not just the number
Two powers are easy to miss. First, the increase takes effect no earlier than the payment date following the determination, so time spent waiting is time at your old rent. Second, where paying from that date would cause undue hardship, the tribunal can push the start back by up to a further two months. You have to ask, and you have to evidence it: income, benefit entitlement, dependants, arrears risk. Put it in the application rather than saving it for later.
Separately, if you moved in within the last six months and think the rent you agreed was above market, you can ask the tribunal to determine that starting rent. Same form, same fee.
Ground 1 and Ground 1A
The usual fear is retaliation. Section 21 is gone, so a landlord annoyed by a challenge cannot simply serve two months' notice and be rid of you. What remains are the possession grounds, and the two that worry tenants are Ground 1 (the landlord or a close family member moving in) and Ground 1A (selling).
Neither is available during the first 12 months of the tenancy, and both require four months' notice. A landlord who obtains possession on Ground 1A is then barred from re-letting or marketing the property for letting for 12 months from the earliest possession date given in the notice, on pain of a penalty. That is a genuinely expensive bluff to call.
So the honest risk assessment: a landlord who wants to sell will sell whether or not you challenged. A landlord who invents a sale to punish you is taking on a year of empty property and enforcement exposure to win back £120 a month.
When negotiating beats applying
A tribunal application is the right move when the proposed increase is well above the ONS trend for your borough, when the flat has real defects, or when the landlord has form for ignoring you. It is the wrong move when the increase is modest and you want to stay several more years.
The direct approach costs nothing and takes one email. Something like: "I've had the Form 4A proposing £1,750 from 1 November. ONS puts London rent inflation at 2.2% in the year to June, and comparable one-bedroom flats within ten minutes of the station are advertised between £1,580 and £1,640. I'd agree £1,600 today and sign nothing further. Otherwise I'll refer the notice to the tribunal before 1 November, which I understand delays any increase until the determination."
That last sentence does the work. Once served, a Section 13 notice cannot be withdrawn unilaterally; landlord and tenant can only agree a different figure in writing. Get any agreed compromise confirmed by email, with the new figure and the date it starts, before you change a single payment.
Do not pay the new figure by accident
If you intend to challenge, leave your standing order alone. Paying the proposed rent, even once, invites the argument that you accepted a new agreed rent and that the notice never needed the tribunal's attention. Keep paying exactly what you paid before, keep the bank records, and let the £47 do its work.