$8.3m luxury London apartment repossessed

Yard Sale Sign

An apartment in one of the world's most prestigious buildings is on sale for £5.25 million ($8.3 million) after being repossessed.

Mystery remains over which of the building's secretive tenants has been forced to sell, with either an Irish property investor or a Dagestani potash tycoon tipped as the forced seller.

Sources in the London property world are divided over which of the owners of apartments in the One Hyde Park, development, notorious as the most expensive per square foot in London, had been forced to put up an "entry-level" apartment for sale through agents Strutt & Parker, who did not return calls Tuesday.

Several said the one-bedroom apartment, in a building where the most expensive flat famously went for around £100 million, was once owned by Ray Grehan, an Irish property entrepreneur who went bankrupt in the U.K. recently.

Grehan was previously embroiled in a dispute with Ireland's National Asset Management Agency over whether it still counted as part of his assets after it was sold to a company linked to his family trust. The mortgage on the property is with Barclays, who may have appointed the agents.

(Read more: I hope we've touched the bottom in Europe: Pirelli )

Others in the property world claimed the flat was owned by Suleyman Kerimov, the Dagestani potash billionaire, although one source pointed out the flat would probably not be expensive enough for him. Kerimov, formerly a close ally of Russia's President Vladimir Putin, has an estimated worth of $7.1 billion, according to Forbes.

However, he recently got into trouble with the government of Belarus, and is now wanted over charges of abuse of power, according to Belarus' state media.

Neither Kerimov or Grehan returned calls from CNBC yesterday.

The development, put up by developers Candy & Candy, designed by architect Lord Rogers and backed by Qatari money, has become well known for being mainly owned by wealthy out-of-towners. Out of 76 apartments for which Land Registry records are available, only 12 are registered to people. The rest are officially owned by corporations, only three of which are based in London, according to Vanity Fair .

It has become an emblem of the excesses of London's luxury property market-and the fact that one flat has been repossessed is quickly becoming a symbol of the pitfalls facing even the wealthiest post credit crisis.

-By CNBC's Catherine Boyle. Follow her on Twitter @cboylecnbc.

Related Stories

JefferiesAnd the Best Place to Work in the global financial markets 2018 is...

Register for HITC Business News