Challenge 
Mansion tax in Kensington
By Simon Dredzen, active in the prime central London property market for over two decades · Reviewed 8 November 2026
Kensington has one of the highest concentrations of £2m+ homes in England. From HM Land Registry sales in W8, SW7 and SW5 since January 2024, brought to April 2026 prices, here is how homes there fall across the mansion tax bands, and how many sit just above a threshold.
Sales by mansion tax band
| Value at April 2026 prices | Yearly charge | Sales |
|---|---|---|
| £2m to under £2.5m | £2,500 | 116 |
| £2.5m to under £3.5m | £3,500 | 141 |
| £3.5m to under £5m | £5,000 | 77 |
| £5m or more | £7,500 | 136 |
Of the £2m+ sales, 266 were flats and 204 houses. The typical (median) £2m+ sale was worth about £3.2m at April 2026 prices.
Why being near a threshold matters
There is no marginal relief: reaching a threshold means the whole higher charge every year until at least the 2033 revaluation. In Kensington, 30% of the recorded £2m+ sales since 2024 were worth less than 10% above a threshold, so a modest difference in value could move them down a band. Another 66 were worth between £1.8m and £2m: an overstated valuation could pull them into the charge.
Valuations will rely heavily on an automated model built from sales data. In Kensington, that model may not see a short lease, a lower-ground floor, a flat without a lift, a busy road or a home in poor repair. Those are exactly the details that move a value by 10%.
What Kensington owners can do now
- Check your home's likely band with our free checker, built on these same sales.
- Record your home's 2026 condition while it still reflects the valuation year.
- If you're close to a threshold, get a free personalised preview or book a free consultation.
- Read how to appeal your mansion tax band when draft valuations are published.
Simon's view
“In Kensington, two flats of the same size in the same building can be worth very different amounts. A lower-ground-floor flat, for example, could be worth 20% less than a comparable flat on a higher floor. A short lease, several flights of stairs with no lift, or the need for substantial modernisation can also affect what a buyer would pay.
“A computer-generated valuation may pick up the address and floor area, but it can miss details that matter to buyers, such as how much natural light a flat gets or what work it needs.
“That’s why I’d start gathering evidence now. Dated photographs, lease documents and any survey reports can help show what your home was like in 2026. If you later need to challenge the valuation, you’ll have a record from the time to support your case.” Simon Dredzen
How we worked this out
- Area: postcode districts W8, SW7 and SW5.
- Period: sales completed from January 2024 to September 2026, as recorded by HM Land Registry. Recent months are incomplete because sales take time to register.
- Which sales: standard-price sales of houses and flats (Land Registry category A). Other property types and additional-price entries, such as repossessions and some company and buy-to-let purchases, are excluded. This is a sample of recorded sales, not every home in Kensington.
- April 2026 prices: each sale is brought to April 2026, the valuation date, using our own London price index, built from these sales by postcode district.
- "Within 10% above a threshold": worth at least the threshold but less than 10% above it at April 2026 prices: £2m to £2.2m, £2.5m to £2.75m, £3.5m to £3.85m, or £5m to £5.5m.
- Price per sq ft: from floor areas on energy certificates, for the £2m+ sales where one was found.
See how prices have moved in Kensington on our prime London prices page. Contains HM Land Registry data © Crown copyright and database right 2026, licensed under the Open Government Licence v3.0. You're welcome to quote these figures with a link to this page.
More guides
- How much is the mansion tax?
- Who pays the mansion tax?
- Mansion tax and leasehold flats
- How to record your home's 2026 condition
- Mansion tax appeal: how to challenge or appeal your band
- Mansion tax in Chelsea
Sources: the HM Treasury consultation on the High Value Council Tax Surcharge (closed 14 July 2026), the government's publications on the surcharge, including its response of 28 October 2026, House of Commons Library briefing CBP-10934, and the Finance Bill (Part 3). The Bill sets the bands and who pays; the response confirmed the deferral criteria and exemptions. The valuation date, challenge process, interest rates and other details will follow in the Finance Bill 2026, regulations and guidance, and may change before April 2028. This is general information, not tax, legal or valuation advice.