Police are failing to uncover the true scale of money laundering in the lucrative UK property market because investors' identities are being concealed through offshore tax havens, official data shows.

Figures released by London's Metropolitan Police to anti-corruption NGO Transparency International reveal for the first time that its Proceeds of Corruption Unit (POCU) has investigated the ownership of just 144 properties with a total value of 180 million pounds ($277 million) in the UK since 2007.

The head of the Met's corruption unit believes this figure represents the "tip of the iceberg," however, because more than three quarters of the properties are registered via offshore tax havens to hide their owner's identities, obstructing UK police investigation. Much of the capital is held in accounts in the British Overseas Territories.

Detective Chief Inspector Jon Benton, head of operations at the POCU, confirmed to VICE News that the real total is "very difficult to know."

"If you look at World Bank estimates for annual illicit financial flows, the global position the UK property market holds and how attractive investments are here, then a natural conclusion would be there is a lot more to find," he added.

Transparency International, which completed the analysis of the police data, is calling for new laws to force foreign companies with a property title in the UK to be held to the same standards of transparency required of UK-registered companies

"The lack of access to beneficial ownership information about offshore companies that hold property in the UK is a major barrier for our investigations," DCI Benton said in the report. "Investigators may spend months and years attempting to peel back layers of secrecy in order to uncover how the proceeds of corruption are being laundered in the UK."

'Money is stolen from citizens in states around the world in astronomical proportions.'

The London property market is globally attractive because of the perceived "safety of the investment," and because "it provides a home in this great capital," he added.

At least 122 billion pounds worth of property in England and Wales is held through companies registered in offshore tax havens, according to a 2014 analysis by the Financial Times. A United Nations Office on Drugs and Crime report estimates that, globally, the detection rate for the proceeds of crime by law enforcement is as low as 1 percent.

The Transparency International report reveals that more than three quarters of properties under investigation by POCU over the last 10 years are held through a company incorporated in a tax haven, and almost half the properties were valued at more than 1 million pounds.

The British Crown Dependencies and Overseas Territories such as Jersey, the Isle of Man, and Gibraltar are independent legal jurisdictions but remain the international responsibility of the UK. This means that they benefit from Britain's political stability and a local judicial system based on English Common Law, but do not need to meet the same transparency regulations required of UK-registered companies.

As such, British police can spend years attempting to access information about the owners of companies registered in the territories. Just 31 of the 120 properties under investigation are registered to an individual's name — although this is rarely the actual suspect.

Land registry data analyzed by Transparency International shows that one in 100 London properties are registered to offshore companies — enough to cover more than 2.5 square miles of real estate.

More than a third of foreign company-owned properties are registered in the British Virgin Islands. The rest are registered in Jersey (14 percent), the Isle of Man (8.5 percent), Guernsey (8 percent), Panama (3.4 percent), and unknown locations (2.5 percent).

In the borough of Westminster alone, nearly one in 10 properties are registered in offshore tax havens.

The British Virgin Islands is the most popular tax haven for London investors. Local legislation grants offshore companies complete secrecy over the identity of owners, directors, and shareholders.

Properties owned through companies registered there are also exempt from capital gains taxes, succession taxes, and stamp duties. Politically stable and with a familiar judicial system, creating an offshore company there takes less than 48 hours, according to the report.

"It can sometimes appear quite technical, money laundering," Nick Maxwell, Transparency International's head of research, told VICE News. "What it really means is money is stolen from citizens in states around the world in astronomical proportions.

"One campaign estimates that at least $1 trillion of US dollars is taken out of developing countries each year. That's an absolutely enormous figure."

POCU specializes in the investigation of the theft of assets by foreign politicians, public officials, their family members and associates from the developing world who launder these funds into and through the UK.

A Metropolitan Police spokesperson said, "We welcome Transparency International's report, which shines a light on how the UK property market is exploited by corrupt officials in order to launder money stolen from civilians across the globe.

"It can take years to unpick the layers of corruption and secrecy which ultimately result in the purchase of UK properties.

"The MPS is committed to working with partners across the globe to overcome these issues, and 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 neighborhoods."

Follow Ben Bryant on Twitter: __@benbryant