Our Data Sources
4, William Street has no records in the the Land Registry and a single entry in the EPC database dated September 2021.
We combine this information with public data of neighbouring properties to estimate the property attributes and values.
The local information is scored as 1 out of 5 and is considered of low accuracy.
Price Range & Condition
In very good condition, we estimate 4, William Street would be worth £3,586,656, with a potential rental value of £10,886 per month.
If substantial cosmetic improvements are needed, the estimated sale value falls to £3,176,753, with a rental value of £9,642 per month.
The extent to which decoration affects a property's value depends on its type, size and location.
Energy Efficiency
4, William Street has an Energy Performance Rating (EPC) of C. This is based on the most recent assessment, dated 29 Sep 2021.
The property is connected to mains gas and has single glazed windows. It is heated using Boiler and radiators, mains gas.
Similar Properties Sold Nearby
Land Registry records and our Estate Agent network show 29 sales of comparable properties within 360 metres of 4, William Street across the last 2 years.
Most recently, Flat 18, 1, Lowndes Square, London, SW1X 9EZ, a leasehold flat, sold at £2,450,000 on the 20th April 2022.
Read more about house prices in SW1.
- Sold Apr 2022£2,450,000 | 3 Bed FlatFlat 18, 1, Lowndes Square, London, SW1X 9EZFlat 18, 1, Lowndes Square, London, SW1X 9EZ
- Sold Mar 2022£4,451,000 | 3 Bed FlatFlat 20, Parkside, Knightsbridge, London, SW1X 7JWFlat 20, Parkside, Knightsbridge, London, SW1X 7JW
- Sold Mar 2022£2,500,000 | 3 Bed FlatFlat 14, 1, Lowndes Square, London, SW1X 9EZFlat 14, 1, Lowndes Square, London, SW1X 9EZ
•Nearby is defined as the radius comprising the nearest 2,000 addresses.
More reading links
Properties Let Nearby
Agents in our network have reported 1 letting within 360 metres of 4, William Street across the last 2 years.
The newest of these is Flat 56, Lincoln House, Basil Street, London, SW3 1AW, a leasehold flat let by Maplewood Property in November 2025.
•Nearby is defined as the radius comprising the nearest 2,000 addresses.
Location Comparison
Our analysis of the public data ranks 4, William Street as the 20th largest and the 10th most expensive of the 21 addresses on William Street, London, SW1.
Against the SW1 postcode district average, it is £1.872m more expensive than the typical property.
More reading links
Schools Nearby
- St George's Hanover Square CofE Primary School900 m away
- Holy Trinity CofE Primary School1.0 km away
- St Peter's Eaton Square CofE Primary School1.0 km away
- St. Thomas More Language College1.0 km away
- Westminster City School1.4 km away
- The Grey Coat Hospital1.8 km away
More reading links
Public Transport Nearby
- Knightsbridge|400 m away
- Hyde Park Corner|400 m away
- Sloane Square|1.1 km away
Available Internet Speeds
Ofcom's latest figures show poor internet coverage in this area, which may mean weak or no connectivity.
According to recent data from Ofcom, Slow/none Broadband is available in the area.
Risk of Flooding
Environment Agency data suggests this area has a Very Low risk of flooding.
