A consultation period closes next week with the council due to decide on the application after that.
Robert Davis, Westminster’s deputy leader and cabinet member for the built environment, said: “Westminster city council supports the right kind of growth and is not against all basement development, but they must be carried out in a way that is considerate to local residents and the environment.”
Chelsea owner Roman Abramovich and artist Damien Hirst were both granted planning permission for vast “iceberg” basements earlier this year.
However, high-profile opponents of such extensions include actress Joan Collins and Queen guitarist Brian May.
May, who lives in Kensington, said: “Developments literally destroy the quality of life for neighbours for years on end.
“Decency and common sense demands a change in the law.”
