Challenge a London Rent Rise: Section 13 and Tribunal

Since 1 May 2026 the tribunal cannot raise your rent above the figure your landlord asked for. That single change is the whole reason to read on: the old risk of walking into the First-tier Tribunal and walking out paying more than the notice demanded has gone. HM Courts and Tribunals Service guidance is now explicit, as

LonRes noted in its review of the decisions register, that the determined rent will be lower than or the same as the figure in the landlord's notice

. The application costs £47. And yet

between 2024 and 2025 only 1,532 tenants across England applied to the tribunal for a rent determination

.

That number is going to move.

What actually changed in May

The Renters' Rights Act 2025 received Royal Assent in October 2025 and its first phase took effect on 1 May 2026, abolishing Section 21 and turning all assured shorthold tenancies into periodic tenancies

.

Almost all existing tenancies converted automatically to assured periodic tenancies on that date, ending fixed terms

.

The consequence for rent is blunt.

All rent increases must now follow the statutory Section 13 procedure: no more fixed uplifts, RPI-linked reviews or bespoke mechanisms, even if they are written into your tenancy agreement

. If your agreement contains a clause saying rent rises by CPI plus one per cent each April, that clause is dead weight.

Shelter's legal guidance goes further: an agreement to increase the rent between landlord and tenant is not valid after 1 May 2026 unless it follows service of a valid Section 13 notice.

So the notice is the lever. Which makes the notice the thing to attack.

What makes a Section 13 notice invalid

A notice that fails on any of these points does not increase your rent. You keep paying the old figure.

• Wrong form.

The prescribed form is now Form 4A, and the old Form 4 is invalid from 1 May 2026

.

• Under two months' notice.

You must get at least two months' notice of the increase, meaning the notice arrives at least two months before the new rent starts

.

• Wrong start date.

The Form 4A notes require the proposed start date to give at least two months' notice, comply with the 52-week or 53-week timing rule, and fall at the start of a tenancy period

.

In practice, Shelter's guidance says the new rent should start on the same day of the month that your tenancy started

.

• Too soon after the last one.

Rent can only be increased once in any twelve-month period, and a second notice served within twelve months of the last increase is invalid

.

Shelter also states rent cannot go up in the first year of a tenancy.

• Served by a route your tenancy does not allow.

The notice can be handed to you or posted; it can be emailed only if your tenancy agreement says so

. A WhatsApp message from your landlord is not service.

Two practical notes. First,

tenants no longer need a County Court declaration to challenge an invalid notice: validity can be raised in the First-tier Tribunal

. Second, if your landlord never gave you the paperwork that came with conversion (

the Government's Information Sheet was due to all existing assured periodic tenants within one month of commencement, so by 31 May 2026

), treat that as a signal about how carefully the rest of their admin was done. Ask for a copy in writing. The reply tells you a lot.

The deadlines, in order

Must reach the tribunal before the date the new rent would take effect

| | Form and fee |

Form MR1, £47 application fee

, with

no hearing fee and Help with Fees remission available

| | Acknowledgement and directions |

Usually two to three weeks, with evidence typically due four to six weeks before the decision

| | Decision |

Referral to determination commonly runs eight to sixteen weeks

| | New rent starts |

From the first rent period following the tribunal's decision, not backdated

|

Miss the start date on the notice and the increase simply takes effect. Do not leave it to the final week:

the practical advice is to submit at least four weeks early so there is room to fix anything missing

.

The no-backdating rule is the quiet win.

Any increase takes effect from the next payment date after the decision, and the tribunal can delay it by two further months in cases of undue hardship

. If the proposed rise is £150 a month and the case runs three months past the notice date, that is £450 you never pay, regardless of the outcome.

The Government set the fee at £47 precisely because it judged access to justice in rent appeals to be acute, against an average cost to the taxpayer of more than £900 per Property Chamber case.

Building your comparables

The tribunal determines open market rent for your flat, in its actual condition, on the actual terms. That is an evidence exercise, and most people lose it before they start.

LonRes read 200 published market rent determinations and found that in almost half of the decisions that gave reasons, the evidence was thin, one-sided or missing altogether, with panels falling back on their own knowledge of the local market

.

In one Romford case the panel recorded "insufficient evidence" and set the figure using its own knowledge of the local rental market.

Start with the ONS Price Index of Private Rents, which publishes borough-level figures monthly. It establishes the direction of travel before you argue about your specific flat, and London is not moving as one market:

£2,843, up from £2,697

|

+5.4%

| | Westminster |

£3,168, down from £3,251

|

-2.5%

| | London |

£2,302, up from £2,252

|

+2.2%

| | UK |

£1,388

|

+3.3%

|

Source: ONS Price Index of Private Rents, July 2026 release.

Kensington and Chelsea remains the most expensive local area in the UK at £3,596.

That Islington-versus-Westminster gap is the point. A Westminster landlord asking for six per cent is arguing against the official index for their own borough. An Islington landlord asking for five is roughly with it, and

the ONS breakdown for Islington shows flats and maisonettes up 5.7% and one-bed properties up 6.0%

, so drill into the property type rather than quoting the borough headline if the detail helps you. If it does not help you, do not raise it. The panel will find it anyway.

Then the specific evidence.

GOV.UK's tribunal guidance says information from letting agents or portals such as Rightmove and Zoopla can help, but evidence from actual agreed lettings is stronger.

That distinction has already decided cases.

In an early determination under the new regime concerning a build-to-rent flat at Skylark Point in London, the tenant relied on advertised rents for similar flats while the landlord produced achieved rents from the same and an adjoining development; the tribunal preferred the landlord's evidence. The rent was £3,102, the landlord sought £3,180 and the tenant proposed £3,040.

Practical version of that, doable this week:

1. Screenshot three to five close matches, with dates.

Three to five strong comparables persuade more than ten weak ones

: same postcode district, same bedroom count, same floor and condition, advertised in the same period as your notice. 2. Log the listings that vanish quickly versus the ones sitting at the same price for six weeks. A flat advertised in April at £2,400 and still live in August is not evidence of £2,400. 3. Ask two local letting agents for a written appraisal of your flat.

An agent's written market appraisal carries real weight, particularly where they manage similar lettings, and two independent valuations beat one.

Say you are considering letting a similar flat and want a realistic figure, or simply ask straight out for a rental valuation. 4. Photograph the defects. Single glazing, a hob with two working rings, mould in the bathroom, no working extractor. The tribunal values the flat as it is, not as the brochure describes it. If your EPC is poor, that is a separate lever worth pulling too, covered in our piece on energy retrofit rules and London rent. 5. Pull your payment history.

Achieved rents beat asking prices

, and the rent you have reliably paid on time for three years is an achieved rent. Bank statements or an app export will do, as we covered in rent payment apps and open banking.

The email that settles it without a tribunal

Most landlords do not want a three-month delay and a written determination on the public register. Send this within a week of the notice, by email, and keep it short:

Thank you for the Form 4A dated [date] proposing £X from [date]. I want to stay and I would rather agree a figure than refer this.

The ONS Price Index of Private Rents for [borough] shows average private rents at £[figure] in June 2026, [up/down] [x]% on the year. I have attached four current listings for comparable [one-bed] flats in [postcode district], at £[range], and two written appraisals from [agents]. The flat has [single glazing / no extractor fan / the outstanding repair reported on [date]].

On that evidence £Y is the market figure. I will agree £Y from the date in your notice and set up the standing order this week. If we cannot agree, I will refer the notice to the First-tier Tribunal before [start date], which under the Renters' Rights Act means no increase takes effect until the first rent period after the decision.

Three things are doing the work there: you are staying, you have evidence, and you are naming the delay without threatening anyone.

Whatever you agree, get it in writing including the date the new rent starts

, and remember that the agreement only bites because a valid notice was served first.

When challenging is the wrong call

If you are paying visibly below market and the notice is competent, a referral invites a panel to write down the market figure.

Landlord guidance is already advising that where a reliable tenant is materially below market, a modest, evidenced increase is less likely to be challenged

, which cuts both ways: accept the modest one.

If you plan to move within six months, the maths rarely works. You will spend hours on evidence to defer an increase you were going to escape anyway. Better to spend that time on where you are going, and our areas guide for young professionals is a faster route to that answer.

If the notice is invalid, do not refer it as a rent case by reflex.

An invalid notice does not increase the rent

, so the cheaper move may be to write to the landlord identifying the defect and keep paying the existing rent. Get advice before you rely on that: if you are wrong about the defect and you have let the start date pass,

you will owe the increase from the date on the notice

.

And if your real complaint is the state of the flat rather than the number, the rent case is the wrong forum. Report the disrepair, in writing, with photographs and dates, and let that evidence do its own job.