The First-tier Tribunal cannot put your rent up. Since 1 May 2026 the worst realistic outcome of a challenge is the figure your landlord already asked for, the increase cannot be backdated to the date on the notice, and the application fee is £47 with no separate hearing fee, as the Ministry of Justice confirmed in March. Generation Rent, which had campaigned against a higher charge, noted the same three points: no backdating, no rent above the landlord's own proposal, and much less exposure to retaliatory eviction now that Section 21 has gone.
The numbers on outcomes are striking. The charity Z2K, arguing in May that even £47 is a barrier, published analysis showing that more than 71% of market rent applications brought by renters succeed in producing a rent lower than the landlord proposed, that successful challengers end up on average £1,140 a year better off than if they had accepted, and that where the tribunal applies a deduction from the baseline market rent the average reduction is £2,160 a year. In 77% of those cases the deduction was for the condition of the property.
That last figure tells you what a winning case looks like. It is rarely a clever legal argument. It is photographs of a mouldy bathroom next to three listings for better flats at the same rent.
The only lawful way your rent can go up
From 1 May 2026, all assured tenancies in England are periodic, and rent on a periodic assured tenancy can only be increased by a section 13 notice on the current prescribed Form 4A, with at least two months' notice, and no more than once every 12 months. Trowers & Hamlins summarised the position bluntly ahead of implementation: rent review clauses in existing tenancy agreements cannot be used for new increases after 1 May 2026.
So if your agent emails to say the rent is rising in six weeks because clause 4.3 of your agreement provides for an annual CPI uplift, that clause is dead. Practitioners writing for landlords now take the same line: a letter, an email, a new agreement at a higher rate, and informal consent are all legally ineffective on a periodic assured tenancy. Only a valid Form 4A notice binds you. If you are unsure what your agreement actually says about rent, our guide to understanding tenancy agreements covers the clauses worth reading twice.
What makes a notice void
Check these before you think about the tribunal. A defective notice is better than a challenge, because you keep paying your existing rent and the landlord has to start again.
| Check | What to look for | Effect if wrong |
|---|---|---|
| Form | The current Form 4A from GOV.UK, completed in full. Old Form 4 versions and saved templates are a common failure | Notice defective, must be re-served |
| Notice period | At least two months between service and the start date of the new rent | Void |
| Start date | Must fall on the first day of a rental period, so the same day of the month your rent is normally due | Void; a mid-period start does not work |
| Gap since last increase | The new rent must not begin earlier than 52 weeks after the date your rent last went up | Void |
| Details | Correct address, correct current rent, and any council tax, water or fixed service charges included in the rent stated properly | Defective if the error affects your understanding of the notice |
The tenancy start date matters here, so dig out the original agreement rather than trusting the agent's records. Openrent's own guidance to landlords, published on the day the Act commenced, concedes that a notice attempting to start rent mid-period or with insufficient notice is invalid.
The pre-May 2026 complication
Two transitional provisions in the Renters' Rights Act 2025 (Commencement No. 2 and Transitional and Saving Provisions) Regulations 2026 deal with the changeover, and both can decide your case.
One covers a rent increase made under a rent review clause before 1 May 2026. If your rent went up in, say, February 2026 under an old review clause, that increase is the one the 12-month clock runs from. A landlord who used a review clause in the spring and then served Form 4A in June for an August start has probably served a void notice.
The other covers section 13 notices given before 1 May 2026. Those older notices are treated under the previous rules, which means the protections you are relying on, including the bar on the tribunal setting a rent above the landlord's figure, may not apply. Check the date the notice was served, not the date the increase starts. If it was served in April, take advice before applying.
Existing tenants should also have received the government's Renters' Rights Act information sheet by 31 May 2026. If nothing arrived, that is a fair indication of how carefully your landlord is handling the rest of the regime.
Applying: the two dates that matter
The application to the First-tier Tribunal (Property Chamber) for a determination of market rent must be made before the date the new rent is due to take effect. Miss that, and the increase simply happens.
So the sequence for this week, if a Form 4A has landed:
- Diarise the start date on the notice. That is your deadline.
- Run the four validity checks above. If the notice fails one, write to the agent, in writing and by email, saying you do not accept the notice as valid, give the reason, and state that you will continue paying the current rent.
- Keep paying the existing rent in full, on time. Arrears are the one genuine risk in this process.
- Start collecting comparables now, dated and screenshotted, rather than the week before the hearing.
- Apply, paying the £47 fee. If money is tight, the Help with Fees scheme applies to these applications.
Because an upheld increase takes effect only from the date of the tribunal's decision, a challenge delays the higher rent whatever the outcome. This has not gone unnoticed by the judiciary: Sir Geoffrey Vos, Master of the Rolls, warned the Housing Law Practitioners' Association that the rules create "an incentive for tenants to apply to the First Tier Tribunal in respect of every increase" simply to postpone it. Expect the tribunal to be alert to that, and expect it to reward applicants who bring real evidence.
Building comparable evidence that a tribunal will accept
The tribunal decides what rent the property could reasonably command on the open market, let by a willing landlord on the same terms. Two official sources should anchor your case, and neither costs anything.
The ONS Price Index of Private Rents, published monthly in the Private rent and house prices bulletin, gives average rents and annual rent inflation for London and for individual boroughs, broken down by number of bedrooms. Use it for direction of travel: if borough-level rent inflation is running well below the percentage your landlord is asking for, say so and cite the month of the release you used.
The mayor's London Rents Map at london.gov.uk, built on Valuation Office Agency data, gives lower quartile, median and upper quartile rents by area and property size. It is more granular than the ONS index and it is the source a London tribunal will recognise. Screenshot the figures with the date visible.
Then add live evidence, because indices lag and listings do not. Aim for six to ten currently advertised flats that genuinely match yours:
- same borough, ideally the same postcode district and the same walking distance to the same tube or Overground station
- same number of bedrooms and, for flat shares, the same arrangement
- same furnishing status, since furnished and unfurnished are not comparable
- similar floor level and type, so a ground floor maisonette against a ground floor maisonette rather than a new-build second floor flat
- similar EPC rating and bills arrangement
For each, keep the URL, the asking rent, the date, and a screenshot. Note that asking rents are not achieved rents, and say so in your statement: it strengthens your credibility rather than weakening your case.
Finally, document condition, since that is where the deductions come from. Photograph damp, single glazing, a broken extractor fan, a boiler that has been reported four times. Attach the repair emails with dates. If your landlord has ignored a request for six months and is now asking for market rent, the tribunal will hear the mismatch.
The risks that remain
Section 21 has gone, but section 8 has not. A landlord who wants you out still has grounds, including moving in themselves or a family member, and Ground 1A where they intend to sell. The commencement regulations include a saving provision on Ground 1A for legacy assured tenancies, so if your tenancy predates the shorthold era, take specialist advice on which grounds are actually available against you.
The practical risks are narrower than most renters fear:
- Rent arrears. Never withhold the disputed portion instead of applying. Pay the existing rent, keep the account clean, and let the tribunal decide.
- Souring a relationship you depend on for references and repairs.
- Your rent being set at market rate when you are currently paying below it. If your comparables come back higher than the landlord's figure, the tribunal cannot go above his number, but you have learned something: settle.
When negotiating beats litigating
If the gap is £40 a month and the notice is valid, the tribunal is not worth your evening. Try this with the agent, in writing: "I've looked at the London Rents Map and the ONS rent figures for the borough, plus current listings for comparable flats nearby. The proposed rent is above what similar flats are being let for, and the bathroom extractor has been outstanding since March. I'd like to agree £X, and I'll commit to staying put." Agents price void periods and re-letting costs into their advice, and a reliable tenant who will not need chasing is worth real money to a landlord.
Where the gap is large and the flat is tired, apply. And if you conclude the flat is simply not worth what is being asked, the market has been producing genuinely cheaper options in odd corners of the city: our piece on newly subsidised flats in London is a better use of an afternoon than a bad settlement.
Whatever you decide, keep the notice, the envelope, the emails and the dated screenshots in one folder. A tribunal determination fixes your rent for the next 12 months, and the same paperwork will do the job again next spring.