Seventy-three percent of tribunal decisions came in below the landlord's proposal. But in 47% of those cases the problem was evidence, not the market. That is a solvable problem, and the landlords who fix it are separating themselves from the half of the sector still frozen by fear of the tribunal.
What Has Happened?
The Section 13 process under the Renters' Rights Act has been running for five months. From 1 May 2026, Section 13 of the Housing Act 1988 became the only legal route to increase rent on an assured periodic tenancy in England. Landlords serve Form 4A, give at least two months' notice for monthly tenancies, and can only increase rent once per 12-month period. Tenants who want to challenge apply to the First-tier Tribunal for Residential Property, which sets the rent at the local market rate rather than ruling on whether the proposed increase is reasonable. The tribunal cannot set the rent above the landlord's proposal.
LonRes, the London-focused property data company, analysed 200 market rent determinations from the First-tier Tribunal and published its findings in October 2026. The headline result: 73% of decisions came in below the landlord's proposed rent. The more useful finding: 47% of the reasoned decisions contained identifiable evidence problems, cases where the landlord's presentation of the comparable market rate was incomplete, relied on the wrong type of evidence, or was absent altogether.
The volume of cases is growing fast. Ministry of Justice data, reported by MPAMAG in October 2026, showed Section 13 applications increased 58% after the RRA took effect on 1 May 2026. Daily applications went from an average of 6.9 in the three months before the Act to 10.8 in the six weeks after. ARLA Propertymark's past president Greg Tsuman made a public call for clearer evidence guidance in October 2026, noting that tribunal caseworkers assess rents actually achieved in the local market, not asking rents from property portal listings. That distinction turns out to be the core of the problem.
On 9 September 2026, the government announced that responsibility for initial rent challenge decisions will move from the First-tier Tribunal to HMRC's Valuation Office. No implementation date was confirmed. Until the new system is in place, the First-tier Tribunal handles all challenges, and the LonRes dataset is the most comprehensive guide to how those cases go.
Why This Matters to UK Property Investors
The 73% figure is the one most landlords have heard. If seven in ten cases go against the landlord, avoidance looks like the rational response. That is why TDS Charitable Foundation data from this week showed 50% of English landlords held rents flat in the past year, up from 39% the year before. The deterrent is working.
But the LonRes analysis cuts across the narrative. If 47% of losses trace to evidence problems, the 73% outcome rate is not an accurate picture of what happens to a landlord who presents their case properly. A landlord who serves Form 4A with correctly selected comparable evidence, achieved rents rather than asking prices, drawn from properties of the same size, type, and postcode, is in a different category from a landlord who submits a notice with nothing more than their own estimate of what the market should be.
This matters commercially. The ONS reported average UK private rents up 3.8% in the 12 months to September 2026. UK CPI ran at 3.5% in September. A landlord who applies Section 13 annually to bring rent to the local market rate is running a real-terms neutral or slightly positive position. A landlord who holds flat is running a declining real yield, quietly, every quarter. At 3.5% inflation, a frozen £850 per month rent is worth £820 in real terms after 12 months. After three years it is roughly £770. Across a portfolio of eight properties held at frozen rents for three years, the compounding effect is significant, and none of it shows up in the headline yield figure until someone does the arithmetic.
The investor angle is this: the landlords frozen by tribunal fear are handing a yield advantage to the landlords who are not. That gap is real now and it compounds over time.
The Risks Investors Need to Understand
The central risk is misunderstanding what the tribunal actually uses as evidence. LonRes found that the most common evidence problem was the use of advertised asking rents rather than achieved rents. A Rightmove listing showing a flat advertised at £1,000 per month is not useful comparable evidence in a tribunal setting. The tribunal looks at rents actually agreed in new tenancy agreements, reflected in deposit protection records, ASTs, or agency let records. An asking price that was never agreed tells the tribunal nothing about what comparable tenants actually paid.
This is a practical problem in lower-turnover markets. A landlord with a mid-terraced house in an area with low letting activity may have limited access to achieved comparable rents. Letting agents in the postcode hold their own let records but those are not public data. Markets in central Manchester, Liverpool, or Leeds have high enough letting turnover that a local letting agent will have multiple comparable achieved rents from the last 12 months. Markets in smaller towns or rural areas with lower density rental supply make that evidence harder to compile.
The annual lock-in is the second structural risk. Section 13 increases can only take effect once per 12 months. There is no mechanism for a cumulative catch-up. A landlord who holds flat this year starts from the same frozen base in 12 months. Missing the annual window is a one-year delay that cannot be recovered through the Section 13 process.
The VOA transfer creates a further consideration. The government announced in September that the Valuation Office will eventually handle initial rent challenges. The VOA uses its own market rent assessment methodology, which is similar to but not identical to the comparable-evidence approach the First-tier Tribunal uses. Landlords who run Section 13 reviews now are working with a system where 200 cases of outcome data exist. The VOA process, when it launches, will be new territory for everyone. There is a reasonable argument for acting under the current rules rather than waiting for a transition with no confirmed date.
Tenants who challenge a Section 13 increase do not pay the proposed rent until a final decision is reached. The challenge costs them £47 (per the 2026 fees order). The financial incentive to challenge a reasonable increase is real for cost-conscious tenants. A well-evidenced Section 13 notice, sent to the tenant with the comparable evidence attached, reduces the likelihood of a challenge by making the market rate visible before the tenant decides whether to contest it.
Where the Opportunity Could Be
For landlords who build their evidence base correctly, the practical opportunity is substantial. If the outcome rate for properly evidenced cases is materially better than 73%, those landlords are getting increases through that the headline figure obscures. The LonRes 47% evidence failure rate suggests that properly prepared cases have a meaningfully different outcome profile, though the report does not split results into evidenced and non-evidenced groups explicitly.
For investors looking to acquire, the below-market-rent opportunity becomes more specific in light of this analysis. A landlord who held rents flat because they feared the tribunal did not have a structural problem with Section 13. They had an evidence preparation problem. A buyer who acquires that property and serves a well-evidenced Section 13 notice in year one is not facing the same process the original landlord was afraid of. They are facing a different process, one where the evidence work has been done.
The cities where this works best are the ones with strong letting agent networks and enough turnover to provide multiple achieved comparables. Liverpool, Manchester, Leeds, Birmingham, Nottingham. A letting agent in any of these markets will have 10 or 15 comparable lets in the relevant postcode from the last 12 months. That is a strong evidence base for a Section 13 review. Compare that with a less active market in a smaller town where the letting agent might have two comparables, both from eight months ago, both from slightly different property types. The evidence quality difference is real and it affects the outcome.
Property Investor App gives investors access to the landlord-to-landlord network, including sellers running below-market rents who have not been through a Section 13 review. For buyers who know how to evidence a correct increase, those properties represent a yield improvement that requires no capital expenditure and can be actioned in the first year of ownership.
Arsh's Investor View
This LonRes analysis confirms what I have been saying to investors since May: the Section 13 process is not as hostile as the 73% headline makes it look. The problem is not the process. The problem is that landlords are walking into the tribunal with the wrong evidence, or no evidence at all, and then blaming the outcome on the process itself.
I have served Section 13 notices in Wolverhampton and across the Midlands. What I do is straightforward. I get comparable rents from my letting agents' most recent let records in the same street or postcode. Not Rightmove asking prices. Actual agreed rents from tenancy agreements completed in the last six months, on properties of the same size and type. I also send the tenant a covering letter with the evidence pack attached so they can see the market rate before they decide whether to challenge. Most tenants do not challenge when the evidence is presented clearly, because the cost of challenging (time, uncertainty, and a £47 fee) is not worth it when the landlord's proposed figure tracks what comparable tenants actually paid.
The landlords who are frozen by tribunal fear are, in many cases, avoiding a perfectly winnable process. I find that frustrating, because the consequence is real yield erosion that compounds silently. The average UK private rent was up 3.8% year-on-year to September 2026. A landlord whose last review was in 2024 is sitting further behind market every quarter, without any corresponding benefit from that position.
On the VOA transfer: I think it will probably be a more consistent process for landlords who evidence correctly, because the VOA's methodology is more systematic and less dependent on individual caseworker interpretation. But the timing is unknown, and the current First-tier Tribunal process is documented in 200 cases of data. Acting now on solid evidence makes more sense than waiting for a transition with no confirmed date.
How Property Investor App Can Help
Property Investor App gives investors access to current market rent data across UK regions, a letting agent network that holds achieved comparable rent records, and the landlord-to-landlord deal network where below-market-rent properties are available before they reach the open market. For investors who want to model the yield improvement available through a year-one Section 13 review on a below-market-rent acquisition, PIA's deal comparison tools let you run the numbers on current tenancy rent, local market rate, and the gap before you bid. For landlords who want to connect with letting agents experienced in evidencing market rent for tribunal purposes, PIA's professional network is the channel to find them. Browse UK property investment opportunities on Property Investor App.
Key Takeaways
- LonRes analysed 200 Section 13 rent increase decisions from the First-tier Tribunal, the first substantial post-RRA dataset in England. 73% of decisions came in below the landlord's proposed rent. But in 47% of reasoned decisions, the underlying cause was identifiable evidence failures, not market rate.
- Section 13 tribunal applications rose 58% after the Renters' Rights Act took effect on 1 May 2026, from a daily average of 6.9 to 10.8 applications. The tribunal service is under volume pressure. ARLA Propertymark called for clearer evidence guidance in October 2026, confirming that tribunals look at rents actually achieved in the local market, not advertised asking rents.
- The critical evidence distinction: the tribunal uses rents agreed in new tenancy agreements, typically evidenced through deposit protection records, signed ASTs or letting agency let records. A Rightmove or Zoopla asking price that was never agreed is not accepted comparable evidence.
- The government announced on 9 September 2026 that HMRC's Valuation Office will eventually replace the First-tier Tribunal for initial rent challenge decisions, with the aim of faster resolution. No implementation date was confirmed. Until then, the existing Section 13 process applies. A tenant who challenges does not pay the increased rent until a final decision. The challenge fee is £47.
- For investors acquiring below-market-rent properties, a well-evidenced Section 13 review in year one is the mechanism to close the gap between current rent and market rate without capital expenditure. The annual window is the only window, and it cannot be used to recover multiple years of frozen increases in a single application.
Frequently Asked Questions
What evidence does the First-tier Tribunal accept for Section 13 rent challenges in 2026?
The First-tier Tribunal looks at comparable rents actually agreed in new tenancy agreements in the local market. This means rents evidenced through signed ASTs, deposit protection records, or letting agency let records, not asking prices from property portals. Letting agents who have recently let similar properties in the same postcode can provide the most useful evidence. ARLA Propertymark confirmed in October 2026 that tribunals compare achieved rents rather than advertised rents. Three to five comparables of the same property type and postcode, with tenancies started within the last 12 months, is a strong evidence base for a Section 13 notice.
Why are so many Section 13 tribunal decisions going against landlords?
LonRes's analysis of 200 decisions found that 73% came in below the landlord's proposed rent, and 47% of reasoned decisions contained identifiable evidence failures. The most common problem was using advertised asking rents as comparables rather than rents actually agreed in tenancy agreements. In low-turnover rental markets, where recent comparable lets are hard to find, the challenge is harder. A landlord who presents correctly selected achieved comparables and limits their proposed increase to a figure those comparables support has a materially different outcome profile than the aggregate 73% figure suggests.
Will the Valuation Office replace the First-tier Tribunal for rent challenges?
The government announced on 9 September 2026 that HMRC's Valuation Office will take over initial rent challenge decisions from the First-tier Tribunal. The stated aim is faster resolutions and less pressure on the tribunal system. No implementation date was confirmed. Until the new process launches, all Section 13 challenges continue through the First-tier Tribunal. The VOA uses its own market rent assessment methodology, which is comparable-evidence based but more systematic than the current caseworker approach. For landlords with well-evidenced cases, the VOA process is expected to be more consistent.
Can I recover years of frozen rent through a single Section 13 notice?
No. Section 13 allows a rent increase once per 12-month period on a periodic tenancy, capped at the local market rate as determined by the First-tier Tribunal if challenged. There is no mechanism to apply a cumulative catch-up in a single notice for multiple years of frozen rents. Each annual review moves the rent to market rate at that point. A landlord who missed the 2025 and 2026 windows cannot bridge that gap in one application. The increase from each annual review becomes the base for the following year. The annual window is the only opportunity to apply.
How do I find comparable rent evidence for a Section 13 review?
Work with a local letting agent who has recent let records in the same area. Agents hold data on rents actually agreed, not just advertised, because they process the tenancy paperwork. The comparables you want are properties of the same type and size, in the same or neighbouring postcodes, with tenancies completed within the last 12 months. Three to five comparables at that level is strong. If the local market has few recent comparable lets, limiting the proposed increase to a figure that even one or two comparables support is preferable to a higher proposal that a tribunal reduces on thin evidence. Some landlords also send the tenant the evidence pack with the Section 13 notice, which often means the tenant accepts the increase without a tribunal application.
