Your landlord has served a Section 13 notice on Form 4A. The rent is going up. You think the new figure is above market rate. Applying to the tribunal is how you challenge it.
Since 1 May 2026, under the Renters' Rights Act 2025, you make that challenge by applying to the First-tier Tribunal (Property Chamber) in England, either online or on Form MR1 ("apply for a determination of an open market rent"). It replaced the older Rents 1 form, which you may have seen written as "RENTS1". The government has announced that HMRC's Valuation Office will take these decisions over, but no date has been set, so for now you still apply to the tribunal (GOV.UK).
What is the MR1 form for?
The MR1 form is a formal application to the First-tier Tribunal (Property Chamber) asking it to determine what the open market rent for your property should be. You use it when your landlord serves a Section 13 notice on Form 4A and you want the tribunal to decide the rent. You can also use it to challenge the rent you agreed at the start of a tenancy, but only within the first six months.
If you apply in time, you keep paying your current rent while the tribunal decides. If your notice was served on or after 1 May 2026 (Form 4A), the tribunal cannot set the rent higher than the figure your landlord proposed, so applying cannot leave you worse off than the notice. This guide covers Form 4A notices from private landlords. If you rent social housing from a housing association and got a Form 4, the older notice, start-date and hardship rules apply and there is no cap, so check GOV.UK's guidance before you apply.
There is an application fee unless your landlord served the notice before 1 May 2026 or you rent social housing, and you may get help paying it if you have little in savings and are on a low income or certain benefits. Check the current amount on GOV.UK.
What does the MR1 form ask you for?
Before you start, gather the notice, your tenancy agreement and 3 to 5 dated listings for similar homes nearby. The current MR1 has 16 sections. Complete every one, and explain on the form anything you cannot provide.
- Type of application (section 1). Say whether you are challenging the rent in a Section 13 notice (you can dispute its validity at the same time), an excessive rent in the first six months of your tenancy, or only the notice's validity. You also say when the notice was served and whether you rent social housing, which decides whether a fee is due.
- Your details and your landlord's (sections 2 and 3). Include any representative or letting agent.
- The notice (section 4). Attach a complete copy and say whether you accept it is valid, and if not, why not.
- Your tenancy (section 5). Your current rent, what it includes, when the tenancy began, and a copy of your tenancy agreement.
- The property (sections 6 to 11). Layout and room sizes, an outside photo and one photo of each room (with nothing personal visible, as these go to your landlord), furniture, services, heating and glazing, any tenant improvements, and who handles which repairs.
- The open market rent (section 12). The figure you think is right and your evidence, such as dated listings for comparable homes. Keep it factual.
- Inspection, hearing and hardship (sections 13 to 15). Ask for an inspection or hearing only with a reason. If paying the new rent from the usual date would cause you undue hardship, say so here with evidence of your finances.
- Fee and statement of truth (section 16 onwards). Pay or give your help-with-fees reference, then sign the statement of truth, which confirms that everything on the form is true.
Send it before the proposed rent start date: online, by email to marketrents@justice.gov.uk, or by post. If you apply by email or post, you should also send a copy of the application and everything attached to your landlord yourself, or the tribunal will send it if you can't. Keep proof.
What happens after you submit the MR1 form?
If you applied online, the tribunal sends your application to your landlord. Your landlord then has 28 days to respond on form MR2, and if they do, you have 14 days to reply on form MR3.
The tribunal often decides on the documents alone. It holds an inspection or a hearing only if it decides one is needed. You do not need a solicitor.
The tribunal will issue a determination setting the market rent. For a Form 4A notice served since 1 May 2026, the new rent takes effect from the date in your notice, or from the start of the next rent period after the decision if that date has passed, and it is never backdated before the decision. The tribunal can set a later start date if paying from that date would cause you undue hardship, but no later than 2 months after its decision. If your landlord served the notice before 1 May 2026, the old rules still apply, so the rent is not capped at the proposed figure and can run from the date in the notice.
Timescales vary with the tribunal's caseload. Attend any hearing the tribunal lists. If you do not attend, the tribunal can go ahead and decide without you.
Common MR1 form mistakes that get applications rejected or delayed
Missing the deadline is the one mistake you cannot recover from. Your application must be received by the tribunal before the proposed rent start date. Miss it and, if the notice is valid, the new rent takes effect as stated and you can no longer ask the tribunal to set a lower rent. Allow time for delivery if you are submitting by post, or use the online service to confirm submission instantly.
The form requires a complete copy of your Section 13 (Form 4A) notice. If you have lost it, ask your landlord in writing for a copy, but do not wait for it if the start date is close. Apply in time and explain on the form why the notice is missing. The tribunal will decide whether the application can proceed.
A vague comparables section gives the tribunal nothing to work with. Three specific listings with dates, addresses and asking rents give it a basis for setting a figure.
What if the Section 13 notice itself is invalid?
A Form 4A notice is invalid if it gives less than two months' notice, if the new rent does not start at the beginning of a rental period of your tenancy, or if the new rent would start less than 52 weeks after your tenancy began or after the last increase took effect. An invalid notice does not raise your rent, as our Section 13 notice guide explains. The tribunal can rule on validity, and the MR1 lets you challenge the notice and the rent together. If there is any doubt, apply before the proposed start date anyway. If there is no Form 4A notice at all, our guide on how to challenge an unlawful rent increase in the UK explains what to do instead.
If you want a second pair of eyes before you file, Remedy can read your tenancy agreement and help you organise the evidence your MR1 relies on.
