The rent increase is huge but still under market: can I challenge it?

Your rent is going up by hundreds of pounds. Maybe it is a 20% jump, maybe 30%, maybe more, all in one go. It lands like a punch, and the first thought is almost always the same: that cannot be allowed, an increase that big has to be something I can fight.

It is one of the most natural reactions there is, and it is also one of the most misunderstood points in the whole rent-increase system. So let us be straight about it, calmly, because getting this right is the difference between a challenge worth running and 47 pounds spent confirming the very increase you were trying to stop.

The size of the increase, on its own, is not what wins a tribunal case. The market rent is.

What the tribunal is actually deciding

When you challenge a Section 13 rent increase at the First-tier Tribunal, the tribunal is not asking "is this increase fair?" or "is this a reasonable amount to put someone's rent up by?" It is asking a single, narrower question:

What would this property let for on the open market today, with a willing landlord and a willing tenant?

That is it. The tribunal works out the open market rent for a property like yours, in the condition yours is in, in your area, right now. Then it sets your rent at that figure.

It does not look at the old rent and the new rent and judge the gap between them. The percentage jump is simply not the test. A 5% increase that pushes you above market can be brought down. A 35% increase that still lands below market can be confirmed in full. The number that decides your case is the market rent, not the distance you have travelled to get there.

Why a huge jump can still be lawful

This is the part that feels counter-intuitive, so here is the logic spelled out.

Imagine your rent has not changed in four or five years. The market around you has moved on, but your rent stayed still. Then the landlord serves a notice that suddenly brings it in line with everything else nearby. To you, it is a shocking one-off leap. To the tribunal, it might just be the rent catching up to where the market already is.

In that situation, the size of the jump is a symptom of the rent having been frozen for years, not evidence that the new figure is wrong. If the new rent matches what similar local properties actually let for, the tribunal can confirm it, big jump and all.

That is why "but it went up so much!" is not, by itself, an argument the tribunal can act on. It is an understandable feeling. It is not a legal ground.

What the tribunal can and cannot do to your rent

Two things are worth pinning down here, because they shape whether challenging is smart.

First, the ceiling. For Section 13 notices under the rules that took effect on 1 May 2026, the tribunal cannot set your rent higher than the figure the landlord proposed. The proposed rent is your worst case. That removed the old fear that challenging could backfire into an even higher rent, which used to put a lot of people off.

Second, within that ceiling, the tribunal sets the market rent, whatever it is. If the market supports the full proposed increase, the tribunal can confirm the full proposed increase. It will not search for a kinder, more affordable middle number out of sympathy. It finds the market figure and applies it.

So the realistic range when you challenge is: somewhere between your current rent and the proposed new rent. You will not end up paying more than proposed. You might end up paying exactly what was proposed, if that is the market. The job before you apply is to work out where in that range the truth probably sits.

What actually gives you grounds

If the size of the increase is the wrong thing to focus on, what is the right thing? Broadly, two routes win cases.

Procedure. The notice itself has to be done correctly. Right form, right dates, the landlord's name and an address for service, proper notice period, valid service. If the notice is defective, you may be able to challenge its validity regardless of the figure, which is a completely separate route from the market argument. A big increase on a sloppy notice is well worth a close look.

Market evidence. If the proposed rent is genuinely above the open market rent for a property like yours, you have real, evidence-based grounds, and the tribunal can bring the figure down. Things that pull the market rent down include:

• Disrepair. A property in poor condition does not command the same rent as a comparable one in good order.
• A poor energy rating. Low energy efficiency is a legitimate factor in what a property is worth to rent.
• Weak local demand. If similar properties are sitting unlet, that tells the tribunal something about the real market level.

Notice that none of these is "the increase is too big". They are all versions of "the proposed rent is above what this property is actually worth on the market, and here is why".

The affordability trap

There is one more thing you need to hear clearly, even though it is the hardest part.

The tribunal cannot take affordability into account. It cannot consider your income, your other costs, your circumstances, or how much of a struggle the new rent will be. None of that is part of the market-rent question, so none of it changes the answer.

This matters because affordability is, for many people, the real issue. A market-rate rent can still be unaffordable. But if the rent is genuinely at market and the only problem is that you cannot afford it, the tribunal is not the tool that helps. The places to look instead are benefits such as the housing costs element of Universal Credit, an honest negotiation with the landlord, or a hard think about whether the home is still the right one. A rent challenge is for "this is above market", not "this is more than I can pay".

How to check before you commit

Here is the practical sequence that tells you whether to challenge or not.

1. Pull comparable rents. Look at what similar properties, same size, type, area, and broadly similar condition, are advertised and let for right now. Property portals, local letting-agent windows, and recent listings are the obvious sources.
2. Compare honestly against your proposed rent. If the asking rents for places like yours sit at or above your new proposed figure, the size of your jump will not save you, and applying risks confirming the increase. If they sit clearly below your proposed rent, you have a real case worth running.
3. Check the notice for defects. Separately from the market, look at whether the notice is procedurally valid. A defective notice can be challenged regardless of the figure.
4. Factor in condition. If your property has real disrepair or a poor energy rating, that strengthens an argument that the market rent for your specific home is lower than the headline figure for the area.

Do that honestly and you will know, before you spend the fee, whether you are walking into a winnable case or an expensive confirmation of the increase.

The bottom line

A huge rent increase is alarming, and the instinct to fight it is completely reasonable. Just aim the fight at the right target. The tribunal does not judge the size of the increase. It judges the market rent, and it can confirm even a dramatic jump if the new figure is at or below market.

Your grounds, when you have them, come from a defective notice or from evidence that the proposed rent is above market, not from the increase being big. Check the comparables, check the notice, be honest about condition, and keep affordability questions for the places that can actually help with them.

If you want a fast, calm read on whether your particular notice is defective and whether the proposed rent looks above market, that free check is the quickest way to find out before you decide anything.