With just two bedrooms it was one of the more modest homes Mayfair has to offer, notwithstanding its impeccable provenance as part of the Duke of Devonshire's Chatsworth estate. But when the house in a quiet cobbled mews went on the market earlier this year it was valued at a cool £1.5m.

If the asking price was startling, the selling price was eye-popping. A total of 14 potential bidders saw it finally sold by Strutt & Parker for £2.77m, 85 per cent above the asking price.