Grosvenor Estates, the Mayfair landlord controlled by the Duke of Westminster, has sold off hundreds of millions of pounds worth of "super-prime" property in London because of fears about the capital's overheating market.
The company posted a third successive year of record profits in 2013 as it took advantage of surging prices to sell off £240m of super-prime developments, typically defined as homes with an asking price of at least £5m. Profits from its UK and Ireland arm more than trebled as a result to £117.5m.
Its chief executive, Mark Preston, insisted that the company was "not calling the top of the market".
But he added: "It's certainly true that part of the reason for making the sales we did last year was because we had a concern about the level of pricing and its sustainability, and the extent to which it was going to continue… Inevitably one has a concern over what happens next."
The move follows research from agents Knight Frank which showed overseas demand pushing up London's luxury-home prices 68 per cent since 2009, compared with a 49 per cent rise across greater London measured by Nationwide.
Grosvenor's sell-offs included 11-15 Grosvenor Crescent, which it sold in December last year for £114m to private developer Wainbridge. The company pumped sale proceeds into rental schemes in more-affordable areas of London such as Bermondsey.
Mr Preston added: "The picture for us looked increasingly risky. One of the things that should concern us all in London is the lack of supply of residential property that can meet the needs of people who want to live and work in central London and cannot afford or choose not to put most or all of their savings into a house."
The company traces its history back to 1677, when the present Duke's ancestor, Sir Thomas Grosvenor, married Mary Davies, who had inherited 500 acres of land north of the Thames to the west of the City of London.
The Grosvenors developed the northern part – now known as Mayfair – in the 1720s before moving south to Belgravia.