Flat 1, 40, Belsize Square has an Energy Performance Rating (EPC) of D. This is based on the most recent assessment, dated 09 Dec 2025.

The property is connected to mains gas and has single glazed windows. It is heated using a boiler and radiators (mains gas).

Flat 1, 40, Belsize Square last changed hands on 8th August 1997, selling for £381,000. The transaction was logged as a leasehold flat by HM Land Registry.

In total it has sold twice since 1995.

• Sold Aug 1997£381,000
• Sold Jul 1996£246,750

Land Registry records and our Estate Agent network show 67 sales of comparable properties within 260 metres of Flat 1, 40, Belsize Square since 2016.

Most recently, Flat 3, 29, Belsize Park Gardens, London, NW3 4JH, a leasehold flat, sold at £1,500,000 on the 3rd October 2025.

Read more about house prices in NW3.

• Sold Oct 2025£1,500,000 | 3 Bed FlatFlat 3, 29, Belsize Park Gardens, London, NW3 4JHFlat 3, 29, Belsize Park Gardens, London, NW3 4JH
• Sold Jul 2025£2,000,000 | 3 Bed Flat10A, Belsize Park, London, NW3 4ES10A, Belsize Park, London, NW3 4ES
• Sold Mar 2025£1,350,000 | 3 Bed FlatFlat 3, 11, Belsize Park, London, NW3 4ESFlat 3, 11, Belsize Park, London, NW3 4ES
• Sold Jan 2025£1,087,000 | 3 Bed Flat19D , Belsize Park, London, NW3 4DU19D , Belsize Park, London, NW3 4DU
• Sold Jan 2025£1,520,000 | 3 Bed FlatFlat 5, 13, Belsize Park Gardens, London, NW3 4JGFlat 5, 13, Belsize Park Gardens, London, NW3 4JG
• Sold Nov 2024£1,550,000 | 3 Bed Flat19C , Belsize Park, London, NW3 4DU19C , Belsize Park, London, NW3 4DU
• Sold Sep 2024£925,000 | 3 Bed Flat31A, Belsize Lane, London, NW3 5AS31A, Belsize Lane, London, NW3 5AS
• Sold Jul 2024£1,563,290 | 3 Bed FlatFlat 5, 42, Belsize Square, London, NW3 4HNFlat 5, 42, Belsize Square, London, NW3 4HN
• Sold May 2024£1,000,000 | 4 Bed FlatFlat 6, 23, Belsize Park, London, NW3 4DUFlat 6, 23, Belsize Park, London, NW3 4DU
• Sold Dec 2023£1,850,000 | 3 Bed FlatFlat 2, 8, Belsize Park Gardens, London, NW3 4LDFlat 2, 8, Belsize Park Gardens, London, NW3 4LD
• Sold Sep 2023£1,337,000 | 3 Bed FlatFlat 2, 29, Belsize Park Gardens, London, NW3 4JHFlat 2, 29, Belsize Park Gardens, London, NW3 4JH
• Sold Aug 2023£1,850,000 | 3 Bed FlatFlat 1, 8, Belsize Park Gardens, London, NW3 4LDFlat 1, 8, Belsize Park Gardens, London, NW3 4LD
• Sold Jun 2023£1,700,000 | 4 Bed FlatFlat 4, 16, Belsize Park, London, NW3 4ESFlat 4, 16, Belsize Park, London, NW3 4ES
• Sold Sep 2022£1,520,000 | 3 Bed FlatFlat 1, 14, Belsize Park, London, NW3 4ESFlat 1, 14, Belsize Park, London, NW3 4ES
• Sold Feb 2022£1,625,000 | 3 Bed Flat15A, Belsize Square, London, NW3 4HT15A, Belsize Square, London, NW3 4HT
• Sold Dec 2020£1,405,000 | 3 Bed Flat37D, Belsize Square, London, NW3 4HL37D, Belsize Square, London, NW3 4HL
• Sold Aug 2020£1,585,000 | 3 Bed Flat14A, Belsize Square, London, NW3 4HT14A, Belsize Square, London, NW3 4HT
• Sold Dec 2019£1,490,000 | 3 Bed Flat18A, Belsize Square, London, NW3 4HT18A, Belsize Square, London, NW3 4HT
• Sold Oct 2019£1,876,000 | 3 Bed FlatFlat 1, 13, Belsize Park Gardens, London, NW3 4JGFlat 1, 13, Belsize Park Gardens, London, NW3 4JG
• Sold Sep 2016£1,700,000 | 3 Bed Flat7C , Belsize Park Gardens, London, NW3 4LB7C , Belsize Park Gardens, London, NW3 4LB

Agents in our network have reported 2 lettings within 260 metres of Flat 1, 40, Belsize Square across the last 2 years.

The newest of these is 3B , Lancaster Drive, London, NW3 4EY, a leasehold flat let by Fine Living in February 2025.

• 
  Let agreed Feb 2025£ Undisclosed | 2 Bed Flat3B , Lancaster Drive, London, NW3 4EY3B , Lancaster Drive, London, NW3 4EY
• 
  Let agreed Mar 2024£ Undisclosed | 1 Bed Flat3A , Lancaster Drive, London, NW3 4EY3A , Lancaster Drive, London, NW3 4EY

•Nearby is defined as the radius comprising the nearest 2,000 addresses.

Our analysis of the public data ranks Flat 1, 40, Belsize Square as the 39th largest and the 36th most expensive of the 264 addresses on Belsize Square, London, NW3.

Against the NW3 postcode district average, it is £104k more expensive than the typical property.

• Rosary Catholic Primary School

  500 m away
• Holy Trinity CofE Primary School, NW3

  600 m away
• St Paul's Church of England Primary School

  800 m away

• The UCL Academy

  700 m away
• Haverstock School

  1.1 km away
• Harris Academy St John's Wood

  1.2 km away

• Belsize Park

  |

  500 m away
• Swiss Cottage

  |

  600 m away
• Finchley Road

  |

  700 m away

Environment Agency data suggests this area has a Very Low risk of flooding.