Revealed: £50m Belgravia home he uses as crash pad

He bought the six-storey stuccofronted regency home in Belgrave Square in April 2003 for an estimated £25 million.

The exact price is not known because he acquired the property through British Virgin Island-registered firm Ravellot, avoiding the requirement to lodge the value with the land registry.

However, even in the current downturn, its worth is likely to have at least doubled since then. The home is permanently staffed with large domestic and security teams, although Mr Deripaska only stays there for a few dozen nights a year. An insight into life at the property was obtained in a May 2007 High Court ruling on a dispute between Mr Deripaska and his former business associate Mikhail Chernoy. The judgment revealed that Mr Deripaska spent a maximum of 27 nights in the house in 2005 and no more than 19 in 2006 up to 13 November. His longest continuous stay was six nights.

He was only in the house with his wife for five nights in 2005 and seven in 2006, and even those visits were interrupted by a business trip to Kiev. The ruling continues: "There was no pattern to his visits to England save that the majority are for one-night stays and involve a constant flow of business meetings."

The only direct glimpse into daytoday life came from the evidence of a courier who had to serve legal documents on Mr Deripaska.

He told the court: "I began to walk up the steps of the property. At this stage a gentleman wearing a suit and white shirt and dark tie... met me at the top of the steps. I said 'good evening sir - are you the butler? He replied in a well-spoken English accent, 'Yes I am sir, can I help you?'". It later emerged in the evidence that the "butler" was in fact a security guard.

Today, two men in dark suits sat outside the home and appeared to be guarding it. A worker at the next-door reside nce said today: "They're incredibly secretive and there's always security guards outside the front door and chauffeurs waiting. I have a Polish friend who works on the security team inside and he says it's a round-the-clock operation."

The house served as a political salon when it was owned by the wealthy Conservative MP and diarist Henry "Chips" Channon in the Thirties. It was known as "Schloss Chips" and visitors included the Prince of Wales - the future Edward VIII - his wife-tobe Wallis Simpson and Winston Churchill.

One visitor described the interior as "very fine indeed".