Earl Cadogan and family
Rank 2017

Not many two-bedroom flats could be described as a "bargain" at £1.2m, but when Margaret Thatcher's former home at Swan Court on Chelsea's Manor Street went on sale earlier this year it was advertised at well under the normal price for such desirable apartments. The reason was that the 1930s property has just 24 years left on its lease, which is owned by Cadogan Estates. The Cadogan family owns 93 acres of Kensington and Chelsea, with nearly half of the £6bn portfolio in retail space. Cadogan, 80, has presided over a hefty investment programme. The Cadogan Charity donated £2m last year, led by £600,000 to the Natural History Museum and £250,000 to Historic Royal Palaces.