Buy-to-let rent increase challenges: how a £47 application can cost landlords months of rent

September 2026 Swift Capital® 7 min read

Since 1 May 2026, putting up the rent on an assured periodic tenancy in England has meant following a strict legal process. Tenants can challenge any increase at the First-tier Tribunal for a £47 fee, and they don’t have to pay a penny more until the tribunal decides. Even if they lose, the new rent only applies from the date of the decision, and they won’t be asked to make up the difference. And there’s a real risk the tribunal sets the rent lower than the tenant pays now. For many buy-to-let landlords, that turns a routine rent review into a costly, time-consuming exercise, and one they may not be equipped to win.

So what does the process involve, why does it weigh so heavily on landlords, and what can you do about it?

How does a rent increase work now?

Under the Renters’ Rights Act, landlords of assured periodic tenancies must use the Section 13 process to increase the rent. That means:

Serving Form 4A, with at least two months’ notice.
Increasing the rent no more than once a year.
Making sure the new rent starts at the beginning of a rental period.

It’s now the only way to raise the rent. Rent review clauses and fixed-percentage or index-linked increases in a tenancy agreement can no longer be enforced, and an informal request by text or email doesn’t count. Tenants don’t have to wait for an increase to challenge either: they can ask the tribunal to review their rent within the first six months of a new tenancy.

If the tenant thinks the increase is above the market rent, they can apply to the First-tier Tribunal before the new rent is due to start. The tribunal then decides the open-market rent, based on the evidence put in front of it.

Three rules make this especially hard for landlords:

The tenant keeps paying the old rent until the tribunal makes its decision.
The tribunal can’t set a rent above the figure in your notice, even if the evidence shows the market rent is higher.
The increase can’t be backdated. It generally applies from the decision, not the date in your notice, so the months spent waiting are lost.

The tenant’s £47 bet

For the tenant, a challenge is close to risk-free. The application fee is £47, and some tenants qualify for help with fees. In the worst case, the tribunal agrees with the landlord and the tenant is £47 out of pocket. Along the way, they’ve avoided paying the increase for several months.

Take a £100 a month increase. If a decision takes three months, as the National Residential Landlords Association (NRLA) reported in September 2026, the tenant saves £300 for a £47 outlay, even if they lose. If the tribunal sets a lower rent, they gain again. That’s not a bad return. As more tenants work this out, challenges are likely to rise, which could overwhelm the tribunal and push waiting times back up, making the bet even better value.

No more workarounds

In the past, some landlords would simply serve a Section 21 notice if a tenant wouldn’t agree to an increase. That option has gone. Landlords now need a valid legal ground to evict, and a tenant challenging the rent isn’t one.

Rent control in all but name?

Some in the property industry have accused the government of introducing rent controls in all but name. Ashley Osborne of Lexit, a service that analyses buy-to-let properties for landlords, said of one recent case: “The landlord asked for £50 more and the tribunal cut the rent by £200, below what both sides agreed at the start. When a third party’s view of market rent can override a rent two people freely agreed, that’s rent control in substance, whatever the act calls it.”

Where do landlords find the evidence?

The tribunal decides on evidence of what comparable properties have actually let for, not what they’re advertised at. That’s where many landlords come unstuck.

Asking rents on property portals are easy to find. Achieved rents, the figures that matter, aren’t published in one place. Letting agents hold that information, but landlords without a managing agent will usually have to pay to access it, whether through an agent, a valuer or a surveyor.

The figures show how often evidence falls short. LonRes, a property data and professional community, analysed a random sample of 200 market-rent decisions made under the previous rules. Of the 169 that gave reasons, 47% described missing or limited evidence, a party submitting nothing, or the tribunal relying on its own knowledge of the local market.

In its review of the first 47 published cases under the new rules, 45 reached a rent decision and two were struck out. None set a rent above the landlord’s proposed figure. In nine, the tribunal valued the property higher but was legally capped at the landlord’s figure.

The hidden cost of every rent review

Even where a landlord’s figure is fair, defending it takes time and money:

Collating comparable lettings and evidence of the property’s condition.
Preparing the tribunal application and, where there’s a hearing, attending it.
Paying letting agents, valuers or solicitors if you need help.

For a modest increase, professional fees can easily exceed the extra rent you’re trying to secure. And because rent can only be reviewed once a year, a landlord could face the same exercise, and the same costs, every year.

We already hear from many landlords who have run up significant professional costs on a range of matters. Rent challenges risk adding to that.

It’s fair to ask whether this was intended. A process that costs the tenant £47 and the landlord far more, with no way to recover the lost rent, does little to encourage landlords to stay in the market.

What do recent figures show?

Challenges are rising. Ministry of Justice figures put the Property Tribunal’s caseload up 56% on a year ago. LonRes counted 113 tribunal decisions in May 2026, 151 in June and 174 in July, compared with roughly 40 a month from January to April. Many of these arose from notices served before the new rules, but the direction of travel is clear. As more tenants see the benefit of challenging, delays could grow.

What about the move to the Valuation Office?

In September 2026, the government announced plans to move these decisions from the First-tier Tribunal to HMRC’s Valuation Office, to speed up decisions and ease pressure on tribunals. No start date or procedure has been published, and it doesn’t change the rules above. Until it happens, challenges still go to the First-tier Tribunal.

Sitting tenants and regulated tenancies

Rent increases for a regulated tenancy, often called a sitting tenant with a protected tenancy or fair rent, are dealt with by a rent officer from the Valuation Office Agency (VOA), and different rules apply. See our article on sitting tenants’ fair rent increases [link to follow] for more information.

What should landlords do before serving notice?

Gather recent achieved rents for comparable properties nearby, noting dates, size, condition and rent.
Record the condition of your property and any improvements you’ve made.
Make sure repairs are up to date, so the tenant has no reason to argue the property isn’t worth the new rent.
Check the notice period, proposed start date and the date of the last increase.
Weigh up the likely cost of defending a challenge against the increase you’re asking for.
Budget for the new rent starting later than planned, even if your figure is upheld.

How the system could be fairer

In our view, if a tenant’s challenge fails, the increased rent should be payable from the date in the landlord’s notice. The tenant should make a reasonable contribution to costs, and the tribunal should be able to set a higher rent where the evidence supports it. If the tenant’s challenge succeeds, the landlord should meet the reasonable costs.

That might protect tenants from excessive increases while discouraging challenges made simply to delay paying, for the price of a £47 fee.

If rising costs and annual rent reviews mean a buy-to-let no longer adds up, selling may be the simpler option.

Thinking of selling your tenanted property?

Swift Capital® buys tenanted property throughout the UK, including buy-to-let properties and those with sitting tenants, rent arrears, tenant disputes, disrepair, live possession proceedings or rent challenges already in progress.

Talk to Swift Capital® in complete confidence for a free, no-obligation offer.

0800 035 0202 | enquiries@swiftcapital.co.uk | www.swiftcapital.co.uk

Sources

General information only, not legal advice. This article covers assured periodic tenancies in England. Take professional advice before serving notice or responding to a challenge.