This article is written with UK readers in mind, however it equally has application in other countries.
Raising the rent used to be a letter. Now it is a case you might have to prove.
On 1 May 2026, the Renters’ Rights Act changed the way Rent Increase notices are issued in England. To increase the rent on a periodic tenancy, there is now one legal route. A Section 13 notice. Rent can only be increased once per year, with 2 months’ notice. The correct form, Form 4A, needs to be issued. If you get the form or the timing wrong, the increase can be invalid, and that’s before we even look at the numbers.
If a tenant challenges the notice, two changes matter most.
First, the tribunal can no longer set a rent higher than the landlord proposed, even if it believes the market is higher. The rent you set is now a ceiling. If you go too low, you could be stuck with an under-paying tenant for at least 12 months.
Second, the tenant has little to lose by challenging. A challenge costs only £47. And the rent isn’t backdated even if the tenant loses. What’s more, Section 21 no fault evictions are gone, so tenants no longer fear reprisal for asking.
Put those together and you get the obvious result. Tenants are challenging.
The floodgates opened
The numbers aren’t subtle. Estate agency Hamptons counted 166 market rent decisions by the property tribunal in July 2026. The monthly average in the year before the Act was 42. That’s a four-fold increase on July 2025. The climb ran 109 in May, 129 in June, 166 in July.
Remove the downside, and every tenant plays the game.
So who wins?
Here is the part landlords need to sit with.
Research by LonRes looked at the first set of determinations made under the new rules. In about 20% of cases, the tribunal valued the property above what the landlord had asked, then capped the rent at the asking price. Ask too low and you are stuck with it.
But it’s not just about the numbers. Proof plays a big role now. In a review of 200 tribunal rent decisions from July 2026, LonRes found that nearly half of the reasoned decisions rested on missing evidence, thin evidence, or the panel falling back on its own knowledge of the local market.
The lesson is simple. The increase does not stand on what you want. It stands on what you can demonstrate.
The first cases tell the story
Let’s look at two real Build to Rent decisions with 2 opposite outcomes.
Case one: Get Living, at Skylark Point in London. The landlord proposed £3,180. The tenant pointed to four nearby advertised units and argued for £3,040. In contrast, the landlord produced nine lettings actually agreed in the same development and the block next door. The tribunal preferred the agreed rents and upheld the increase in full.
Here is the distinction that decided it: Advertised rents don’t carry the same weight as achieved rents. And furthermore, rents from the same building are more relevant than rents nearby where the location, amenities and quality differ.
This is pretty obvious, although it does raise an important question: Why do BTR operators try to copy pricing from other buildings when they have their own data treasure trove which describes how their own tenants and applicants behave in the exact same building?
Case two. A Build to Rent flat in Margate. The operator had the same idea, they just didn’t execute well. The landlord proposed lifting the rent from £1,030 to £1,250 and pointed to three other units in the building. But the evidence was screenshots from the agent’s own system. The tribunal would not accept these as proof of rents actually achieved. The screenshots, it said, “do not evidence these are achieved lets rather than the proposed rent increases.” The rent was cut back to £1,100.
This case demonstrates the importance of showing achieved rents, not advertised rents.
What evidence actually wins
The pattern across the early decisions is clear. Strong cases look like this:
| Description | Ideal | Less Satisfactory |
| Type of rent | Rents achieved | Advertised rent |
| Recency | Recent lettings | Old figures from last year |
| Sample size | Several comparables | One or two comparables |
| Comparability | Same attributes, Same building | Loosely similar properties |
| Proof | Documented transactions | Vague screen shots |
| Context | Differences explained | Differences ignored |
The better the data, the better the outcome.
This is not just a United Kingdom story
Australian operators should not look away. New South Wales and Victoria already limit increases to once a year and expect landlords to justify them. The specifics differ. The direction does not. Evidence is becoming the currency of rent setting, and the market is moving in that direction.
Most operators do this backwards
Here is how a lot of Build to Rent operators work. They start by looking at the buildings around them. They try to benchmark themselves against the competition. Then, when a tenant challenges, they dig inside their own building for comparables to justify it.
That is backwards. Evidence gathered after the fact, to defend a number you already chose, is not really evidence. It is an alibi. And the Get Living and Margate cases show that the tribunal can tell the difference.
Price Wizard sets the rent the other way round. The achieved rent in your own building isn’t the defence. It is the starting point.
We set each Section 13 price directly from the rents actually achieved by new tenants in the same building, for units with similar attributes. The figure the tenant is asked to pay is built from the same evidence a tribunal wants to see. There is nothing to reverse engineer, because the price was never a guess in the first place.
We don’t need to benchmark against the competition. The tenants do that for us through their decisions to rent or not to rent.
We can even show the rent we would have charged a new tenant in that building, and exactly how the Section 13 figure relates to it. In practice, the Section 13 rent sits at a small discount to the new tenant rent, usually around 0 to 1%. That is deliberate. A sitting tenant is worth keeping, and a modest discount protects the renewal while staying firmly in market territory.
So by the time a challenge arrives, the work is already done. The price is the evidence. The evidence is the price.
The takeaway
The Renters’ Rights Act did not ban rent increases. It raised the standard of proof. The landlords who keep winning will be the ones who set rents from their own achieved data, not the ones who scramble to defend a number after the fact.
Asking rents are a wish. Competitor prices are an opinion. Achieved rents in your own building are a fact.
Price Wizard runs on facts. What do you run on?
Greg Einfeld is the Founder and CEO of Price Wizard, helping Build to Rent operators worldwide optimise their pricing with their own data
