British property is a safe haven for money stolen from around the world, with tens of thousands of London properties owned by secretive companies, according to a corruption report released Wednesday.
Campaign group Transparency International found 36,342 properties in London covering 3.6 square kilometres are held by companies registered in offshore secrecy havens such as the British Virgin Islands, Jersey and the Isle of Man.
Almost one in 10 properties in the district of Westminster, where the British government is based, are owned by a company registered in an offshore haven, the report found.
In 2011 alone, the report said, £3.8 billion worth of UK property was bought by companies registered in the British Virgin Islands.
The group said the use of British property to store stolen wealth may have helped inflate prices -- an explosive political issue due to near-record prices and a lack of affordable housing ahead of Britain's May election.
"There is growing evidence that the UK property market has become a safe haven for corrupt capital stolen from around the world, facilitated by the laws which allow UK property to be owned by secret offshore companies," said Transparency International executive director Robert Barrington.
"This has a devastating effect on the countries from which the money has been stolen, and it's hard to see how welcoming in the world's corrupt elite is beneficial to communities in the UK."
The group urged the government to make the Land Registry require transparency over who owners of companies are, in order to ensure Britain is not "the destination of choice for global corruption".
- Unpicking the layers of secrecy -
The report examined data from the Land Registry along with the Metropolitan Police Proceeds of Corruption Unit.
The police force said it had helped with the investigation as such cooperation was important to improving understanding of corruption and how to address it.
"It can take years to unpick the layers of corruption and secrecy which ultimately result in the purchase of UK properties," a police spokesman said.
"Such properties are often owned by companies registered in foreign jurisdictions and while secrecy jurisdictions have been co-operative with our investigations, obtaining evidence can take years."
"We would welcome any regulation which makes it harder for corrupt officials to hide money that has been stolen from civilians across the world, in our own neighbourhoods."
The campaigners said that £180 million ($277 million, 247 million euros) of property in Britain has been brought under criminal investigation since 2004 -- described as the tip of the iceberg.
Three out of four properties that had been brought under criminal investigation were registered in an offshore secrecy haven, the group said.
The campaigners published a map showing the location of the properties per borough online at ukunmaskthecorrupt.org as part of the report, called "Corruption on your Doorstep: How corrupt capital is used to buy property in the UK".
The investigation comes at a moment when hidden wealth is under scrutiny following a political scandal over allegations top British bank HSBC helped wealthy clients evade tax.
In response to the report, the British government said it was committed to tackling illicit money flows and the misuse of companies.
"We are taking forward world leading reform to improve corporate transparency and working hard to encourage others to take equally ambitious action in this space," a spokeswoman said.