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, and most tenants never do because they don't know they can.
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"). MR1 is the current form. It replaced the older Rents 1 form, which you may have seen written as "RENTS1". The tribunal then determines what the open market rent for your property should be. If it agrees the proposed increase is too high, the new rent gets set at a lower figure. Timing is critical, so don't sit on this.
This guide walks through the MR1 application and how to complete it, in plain terms, so you can submit a clean application without getting lost in tribunal procedure.
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 a landlord proposes a rent increase, by serving a Section 13 notice on Form 4A, and you want to refer the matter to the tribunal for a determination.
Put simply: your landlord says the rent is going up, you disagree with the amount, and applying to the tribunal on Form MR1 (or online) is your mechanism for getting an independent body to set a fair figure instead.
Be clear about what the form does not do. It is not a complaint form. It does not pause your rent automatically. The tribunal's job is to set the market rent, which could come in below what your landlord proposed or at the same level. Under the Renters' Rights Act, the tribunal cannot set the rent higher than the figure your landlord proposed in the Form 4A notice, so applying carries no risk of a worse outcome than the increase you were already facing. Most tenants who use this process do so because the proposed increase is noticeably above comparable properties in their area.
Applying to the tribunal costs £47 from 1 May 2026. A separate form, the RRO1 form, is used for rent repayment order applications, which cover unlicensed HMO properties, illegal eviction, and similar landlord offences. Do not confuse the two. MR1 sets a fair rent going forward, while RRO1 recovers rent a landlord should never have taken. If you are dealing with an offence rather than a rent increase, our guide to how to apply for a Rent Repayment Order in the UK covers that process.
What documents do you need before you start?
Gather everything before you open the form. Tribunal applications with missing documents get delayed, and a delay here can mean missing your deadline entirely.
You will need:
- The Section 13 notice your landlord sent you. This is the formal rent increase notice, now served on Form 4A. Without it, the tribunal cannot process your application.
- Your tenancy agreement. The tribunal needs to confirm you are an assured tenant and to understand the current terms.
- Evidence of comparable rents. This is what wins or loses the argument on quantum. Collect current listings from Rightmove or Zoopla for similar properties in your area: same number of bedrooms, similar condition, same street or postcode district. Screenshot them and note the date. Three to five comparables is usually enough.
- Your current rent amount and the proposed new amount. Both must appear clearly in your application.
- Your contact details and your landlord's contact details. Name, address, email where known.
If you upload a tenancy agreement to Remedy Legal, the platform extracts the key terms and flags relevant clauses automatically, which saves time when you are pulling together the factual background for your application.
The form and the online service are on GOV.UK. Following the submission instructions there helps your application get processed as quickly as possible.
What does the MR1 form ask you for?
The application is not long, but each part matters. Here is the information you will provide and why.
- Type of tenancy. You confirm the tenancy the increase relates to. For most private renters in England this is an assured tenancy. If you are unsure which category applies, your tenancy agreement will specify it.
- Property details. The full address of the rental property, including postcode. This must match the address on the Form 4A notice exactly.
- Landlord and tenant details. Your full name and address, then your landlord's full name and correspondence address. If you only have an agent's address, use that and note it is the agent.
- Current rent and proposed rent. The rent you are currently paying, the proposed new rent, and the date the landlord wants the new rent to start. This date is your hard deadline for submission.
- Grounds for your application. This is where you explain why you believe the proposed rent is above the open market rate. Keep this factual. Reference your comparables: "Three similar two-bedroom flats within 0.5 miles are currently listed at £X, £Y, and £Z per month on Rightmove (accessed [date])." Do not editorialise about your landlord's motives.
- Supporting documents. List everything you are attaching, and attach them in the order you list them. The tribunal receives a lot of applications and clarity here saves time.
- Signature and date. Sign and date the form. For online submissions, you confirm electronically.
Once complete, submit the application and all attachments to the First-tier Tribunal (Property Chamber) before the proposed rent start date. Keep proof of submission.
What happens after you submit the MR1 form?
The First-tier Tribunal will acknowledge your application and notify your landlord. From that point, both sides may be asked to submit further evidence or attend a hearing.
In straightforward cases, the tribunal can decide the matter on the papers without a hearing. In contested cases, you will be invited to attend, usually at a regional tribunal venue. The hearing itself is relatively informal compared to a court. A panel, typically one or two members, will review the evidence and may ask questions. You do not need a solicitor present, though you can bring one.
The tribunal will issue a determination setting the market rent. Under the Renters' Rights Act, that rent takes effect from the date of the tribunal's decision, or a later date up to two months on if backdating it would cause you undue hardship. It is not backdated to your landlord's proposed start date. And while your challenge is pending, you keep paying your existing rent rather than the proposed increase, so you will not be hit with a backdated lump sum.
Response timelines vary by region and current tribunal caseload. Attend any hearing the tribunal lists. Missing it without notice can result in the application being struck out.
For a broader picture of how the First-tier Tribunal handles housing claims, the guide on First-tier Tribunal housing claims for UK tenants covers the general process in detail.
Common mistakes that get applications rejected or delayed
Missing the deadline is the most common and most fatal error. Your application must be received by the tribunal before the proposed rent start date. "Received," not "posted." Allow time for delivery if you are submitting by post, or use the online service to confirm submission instantly.
The second most common problem is submitting without the Section 13 (Form 4A) notice attached. The tribunal cannot process your application without it. If you have lost the original, ask your landlord in writing to resend a copy and keep the email thread.
A vague comparables section kills your chances of a meaningful reduction. Saying "the rent is too high for the area" gives the tribunal nothing to work with. Three specific Rightmove listings with dates, addresses, and asking rents give the tribunal a basis for setting a figure.
Selecting the wrong tenancy type causes administrative delays. Check your tenancy agreement before you confirm it.
Finally, do not confuse the MR1 form with a rent repayment order application, which involves different grounds, a different form (RRO1), and a different legal basis entirely. If your landlord has committed an offence such as operating an unlicensed HMO, illegal eviction, or harassment, a rent repayment order is the correct route. Our guide to the RRO1 form and rent repayment order tribunal process explains the distinction between these two types of applications.
How Remedy Legal can help with a rent increase challenge
Remedy Legal is an AI-powered platform built for UK tenants dealing with landlord disputes, including rent increase challenges. It is not a law firm, but it covers a lot of the groundwork that makes a tribunal application credible. Its tenancy agreement analysis extracts the key terms you will need to reference in the tenancy, property, and rent parts of the form, and its bundle tools help you organise evidence, annotate documents, and track your submission deadline.
If your dispute involves more than a rent increase, the landlord assessment tool checks your situation across multiple compliance areas and flags whether you also qualify for a rent repayment order. If you want to challenge a rent increase, start by sharing your situation with Remedy on WhatsApp for a free initial assessment.
How to challenge an unlawful rent increase beyond the MR1 form
The MR1 application is the right tool when your landlord has followed the correct Section 13 process but proposed a rent you think is above market rate. A different set of rules applies when the rent increase itself is procedurally defective.
A Section 13 notice is invalid if it fails to provide the required notice, at least two months from 1 May 2026, or if the proposed start date does not align with a rent payment date. In those cases, you do not need to apply to the tribunal at all. The notice simply does not take effect.
Some landlords attempt to increase rent outside the Section 13 process entirely, for example by inserting a rent review clause into the tenancy agreement and then acting on it unilaterally. Under the Renters' Rights Act 2025, rent review clauses in assured tenancies are no longer effective. A Section 13 notice on Form 4A is the only route to a lawful increase, so if your landlord is trying to raise your rent and you have not received one, the increase may not be legally enforceable.
For the full picture on procedural defects and what to do when a rent increase falls outside the Section 13 route, see our guide on how to challenge an unlawful rent increase in the UK.
Applying to the tribunal costs £47 and gives you a legally binding determination of what your rent should be. Most tenants facing a steep increase never use it because the process feels opaque. It is not: the application is short, the process is straightforward, and the deadline is the only thing you genuinely cannot miss. If you have received a Section 13 notice and want to understand your position first, upload your tenancy agreement to Remedy Legal for a free instant assessment.
