House prices in William Street, London, SW1X
10 homes have sold on William Street (SW1X) since 1995, the first in 1996. Over the last five years the median sold price was £2,650,000 from 5 sales, 219% above the Westminster median of £830,000and against £2,945,000 across SW1X. Sales here have been flats 100%.
- Median sold price
- £2,650,000
- last five years · 5 sales
- Half of sales were above this price, half below
- Price per sq ft
- £2,735
- based on 5 of 5 sales
- Sales matched to an EPC floor area
- Sales since 1995
- 10
- 3 in the last 12 months
- Latest sale
- £1,500,000
- 20 Jan 2026
- vs Westminster
- +219%
- Westminster median £830,000
Every sale on William Street, SW1X
› Apartment 9, 1 SW1X 9HL · Flats £1,500,000· 20 Jan 2026 · 2 sales
| 20 Jan 2026 | £1,500,000 | Flats · Leasehold | 969 sq ft · £1548/sq ft | first recorded sale |
| 30 Sept 2025 | £2,550,000 | Flats · Leasehold | 969 sq ft · £2632/sq ft | +70% vs 2026 |
› Apartment 6, 1 SW1X 9HL · Flats £23,250,000· 21 Nov 2025
| 21 Nov 2025 | £23,250,000 | Flats · Leasehold | 5,038 sq ft · £4615/sq ft | first recorded sale |
› Apartment 7, 1 SW1X 9HL · Flats £2,650,000· 12 Mar 2024
| 12 Mar 2024 | £2,650,000 | Flats · Leasehold | 969 sq ft · £2735/sq ft | first recorded sale |
› Apartment 4, 1 SW1X 9HL · Flats £15,200,000· 29 Sept 2023
| 29 Sept 2023 | £15,200,000 | Flats · Leasehold | 3,541 sq ft · £4292/sq ft | first recorded sale |
› 1, William Street House, 1 - 9 SW1X 9HH · Flats £270,000· 3 Apr 2009
| 3 Apr 2009 | £270,000 | Flats · Leasehold | first recorded sale |
› Flat 5, William Street House SW1X 9HH · Flats £1,850,000· 16 Aug 2004 · 3 sales
| 16 Aug 2004 | £1,850,000 | Flats · Leasehold | 2,013 sq ft · £919/sq ft | +142% vs 1999 |
| 25 Jul 2002 | £1,250,000 | Flats · Leasehold | 2,013 sq ft · £621/sq ft | −32% vs 2004 |
| 2 Aug 1999 | £763,250 | Flats · Leasehold | 2,013 sq ft · £379/sq ft | first recorded sale |
› Flat 1, William Street House SW1X 9HH · Flats £400,000· 3 Jan 1996
| 3 Jan 1996 | £400,000 | Flats · Leasehold | 1,668 sq ft · £240/sq ft | first recorded sale |
At your size
A 90 m² (970 sq ft) home in SW1X is worth roughly £1.52m–£2.37m at the district's typical £1567–£2445 per square foot (130 sales, two years) — a range, not a valuation.
Check your addressAll sold prices in Westminster· SW1X district on the Westminster page
Track William Street, SW1X
One email a month with the sales newly registered here — no account needed, unsubscribe in one click.
Sources and method. Sales completed to July 2026, as registered by 29 Aug 2026 · headline figures cover the 12 months to May 2026 (later months are still being registered).Next HM Land Registry release ~28 Sept 2026. Medians unless stated; averages only where 30 or more sales. Category A sales only (standard price-paid transactions), houses and flats.
Contains HM Land Registry data © Crown copyright and database right 2021. This data is licensed under the Open Government Licence v3.0. Floor areas derived from Energy Performance Certificate data © Crown copyright, licensed under the Open Government Licence v3.0. Contains OS data © Crown copyright and database right 2026. Contains Royal Mail data © Royal Mail copyright and database right 2026. Source: Office for National Statistics licensed under the Open Government Licence v3.0.
How we calculate these figures · Ask us to hide a sale or correct a record