Two markets, not one
Prime London has stopped moving as a single market. Above roughly £10m it is competitive, international, and quick when the right house appears. Between £2m and £10m it is slow, well supplied, and negotiable. The two halves are being priced by different buyers for different reasons, which is why the same borough can be described as hot and weak in the same week.
The top half is not a rumour. Beauchamp Estates' mid-year survey of £15m-plus deals counted 34 London sales in the first six months of 2026 worth £1.24bn, a 79% increase in transaction value on the same period of 2025. Twenty-four were freehold houses, worth almost £1bn between them. American buyers took 30% of that market and Gulf buyers 25% — more than half between them — according to the agency's survey, published in July.
The band below trades differently. Savills' read on the £5m-plus market, published on 27 July, recorded 107 such sales in the second quarter of 2026: 45% more than the first quarter, but 7% fewer than the same quarter a year earlier. £1.22bn changed hands, the strongest quarter since late 2024. Flats were 29% of £5m-plus sales, the lowest share since 2021, which Savills attributes to softer investor demand. Its research director, Frances McDonald, called the market "improved, rather than accelerating", and pointed at the middle: activity and price growth have been weakest in the £5m-£10m bracket.
What the register records
The official register is less flattering than either. HM Land Registry publishes the UK House Price Index (UKHPI) with the Office for National Statistics; the July 2026 release, covering completed sales the register has processed, appeared on 16 September. This desk pulled the full UKHPI file from that release and built the table below from it — twelve-month averages of the register's own monthly readings, with its monthly sales counts summed for comparable months.
| Area | Average price, 12m to Jul 2026 | 12m to Jul 2025 | Change | Sales, Jan-May 2026 | Sales, Jan-May 2025 |
|---|---|---|---|---|---|
| City of Westminster | £932,605 | £1,048,250 | −11.0% | 522 | 965 |
| Kensington & Chelsea | £1,327,221 | £1,393,595 | −4.8% | 415 | 786 |
| Camden | £837,421 | £863,054 | −3.0% | 526 | 927 |
| London | £553,897 | £563,112 | −1.6% | 23,547 | 38,769 |
| England | £291,634 | £287,294 | +1.5% | 217,376 | 321,714 |
Source: HM Land Registry and ONS, UK House Price Index full file, July 2026 release, 16 September 2026. Desk calculation: the mean of the register's twelve monthly average prices to July 2025 and to July 2026, and its own monthly sales counts for January to May of each year.
Westminster has fallen roughly seven times as fast as England has risen. And the register recorded 45.9% fewer Westminster sales in the first five months of 2026 than in the same months of 2025. Part of that is a comparison effect: March 2025 was an outsized month in the register and March 2026 was not. Take March out of both years and Westminster is still 35.9% lower and London 17.7% lower.
That is the top of the market transacting less, not more. The index-level reading of the London market, and why flats rather than houses carry the fall, is the subject of the desk's read on the July UK house price index. This piece is about what the register says at the top, and what sits under it.
The discount, and what it is measured against
LonRes, which compiles whole-of-market transaction data from London agents, put the average discount to asking price across prime London at 10.4% in the first half of 2026, in its Summer edition published on 30 July — against 8.3% a year earlier. In the £5m-plus market the same measure reached 13.0%, from 10.8%. Average time on the market rose to 186 days. £5m-plus transactions in the first half were 14.7% below last year, though still 15.4% above the pre-pandemic norm, and available stock across prime London was 64.7% above its level at the end of 2019.
Read that against what Winkworth found in its own Summer prime central London report. Homes repriced decisively — by 10% or more — sold at over 98% of their final asking figure. Around one in eight sales exceeded its asking price. And sellers who cut early gave up almost exactly the same total discount as those who waited more than six months, but found their buyer months sooner.
Put the two together and the headline number changes meaning. The 10.4% is measured against an asking price that was, in a large share of cases, wrong when it was set. The discount on offer is not a market-wide markdown; it is the price of starting too high.
The £2m line and the £5m step
Under both of those bands sits the tax that is reshaping how buyers bid. The High Value Council Tax Surcharge (HVCTS) is an annual charge on the owners of residential property in England worth £2m or more in 2026 values. HM Treasury's published guidance, dated 26 November 2025, sets it at £2,500 a year at £2m-£2.5m, £3,500 at £2.5m-£3.5m, £5,000 at £3.5m-£5m and £7,500 above £5m, charged on top of council tax, uprated with CPI from 2029-30, and starting in April 2028. It is expected to raise around £430m a year. Fewer than 1% of English properties are expected to be in scope. Revaluations follow every five years, the next in 2033.
The Valuation Office, not the sale price, decides who is caught: it is running a targeted valuation exercise on 2026 values. That is what makes the line bite. A house bought for £1.95m can be in scope, and one bought for £2.1m can be out of it.
| 2026 valuation | Annual surcharge | Step up at the threshold | Charge as a share of value |
|---|---|---|---|
| £2.0m-£2.5m | £2,500 | first band above the line | 0.125% at £2m |
| £2.5m-£3.5m | £3,500 | £1,000 more than the band below | 0.140% at £2.5m |
| £3.5m-£5.0m | £5,000 | £1,500 more | 0.143% at £3.5m |
| Above £5.0m | £7,500 | £2,500 more | 0.150% at £5m |
Source: HM Treasury, High Value Council Tax Surcharge guidance, 26 November 2025. The step-up column and the share-of-value column are this desk's arithmetic.
The schedule is nearly flat: at no point does the charge exceed 0.15% of value, and the £5m step is the sharpest in it. A home valued just under £5m pays £5,000; just over, £7,500. There is one reason to price under £2m and a separate reason to price under £5m.
HM Treasury's own note makes the political case in a line: the average band D council tax in England is £2,280, which is £250 a year more than a £10m house in Mayfair pays on Westminster's band H rate. The consultation on the surcharge's detail opened on 19 May 2026, ran eight weeks and closed on 14 July. No outcome has been published. Trade press reporting on 21 September had the Treasury weighing a cut in the threshold to £1.5m, which it has not confirmed. The figure matters, because the reported cut would add about 130,000 owners, mostly in London and the south east, to a charge set property by property.
What a Hong Kong family office is choosing between
For a Hong Kong buyer, the two halves of this market offer opposite trades, and the tax line is what separates them.
Above £5m the case is the entry discount and the income. LonRes's prime London yield index stood at 4.82% in the second quarter of 2026, with prime central London at 4.40% — high by London's own recent history. On a £5m house the surcharge is £7,500 a year, about a third of one month's rent at that yield. At the pound's level on the desk's ticker this morning — GBP/USD 1.3363 and USD/HKD 7.8434 at 07:30 HKT, implying about HK$10.48 to the pound — £7,500 is roughly HK$78,600 a year on a HK$52.4m purchase. It is a line in the accounts rather than a reason to walk.
Between £2m and £5m the arithmetic is tighter and the tax proportionally heavier. The same £2,500 to £5,000 lands on a smaller asset, and the buyer's leverage is real: LonRes has stock 64.7% above its pre-pandemic level and price reductions running more than 50% above the long-run average in every month of 2026. If a house is priced at £2.05m, the £2m valuation line is part of the negotiation, not an afterthought.
What to watch on 28 October
The dated checkpoint is the Autumn Budget on Wednesday 28 October 2026, confirmed by the Treasury on 31 July. Three things could move there. The consultation outcome, still unpublished, decides who is liable in complex ownership, how a valuation can be challenged, and whether exemptions land. The threshold could move. And the 2026 valuation exercise decides which houses are actually caught — and it is already running.
Winkworth's summer report put the general point better than any forecast: buyers and sellers can price a legislated tax, not a rumoured one. Until 28 October, prime London's £2m-to-£10m band is negotiating with one eye on a number nobody has published.
