“Once upon a time you came to Mayfair because it’s semi-civilised and the rest of London was a dump,” says Craig McWilliam, chief executive of Grosvenor Group’s UK business. “That’s not true anymore. You can get great office space anywhere now.”

It is tricky to know how far back in time McWilliam is referring to. Grosvenor invests on behalf of the Duke of Westminster and his family, which developed Mayfair and Belgravia from rural pastures, orchards and swampland to the west of the City during the 1700s and 1800s, and which still owns much of the area’s extremely posh addresses.