So-called Unexplained Wealth Orders (UWOs), which came into force on Wednesday, allow authorities to freeze and recover property if individuals cannot explain why they own assets worth more than their income and show they have acquired them legally.

Under the new rules, which are designed to stop corrupt people using Britain as a safe haven, individuals can be fined and jailed if they make misleading statements.

"We have been combing through all existing case work and intelligence and have matters of interest that might transmogrify ...," David Green, the outgoing head of the Serious Fraud Office (SFO), told an audience at London think-tank The Royal United Services Institute (RUSI) on Tuesday evening.

London has long been seen as a favoured destination for corrupt cash. Transparency International, an anti-corruption group, says it has identified 4.4 billion pounds worth of property in Britain that should be considered as possible candidates for UWOs.

It highlighted five properties - four in London and one in the city's commuter belt in Guildford, Surrey - that it said authorities should consider as sources of potentially illicit wealth.

Rachel Davies Teka, head of Advocacy Transparency International UK, said the introduction of UWO's would help combat the fight against "dirty money" flowing into Britain.

"They will allow law enforcement to much more easily investigate assets that are highly likely to have been bought using corrupt money, often stolen from populations in some of the poorest parts of the world," she said.

Green called UWOs an "extremely useful tool" but cautioned that the SFO would not use them until it had the right case.

(Reporting by Kirstin Ridley, editing by David Evans)

By Kirstin Ridley