British Prime Minister David Cameron addresses the Global Investment Conference in London. Photo: Channel News Asia (AFP/Stefan Rousseau)

Cameron sent a letter to 10 British crown dependencies and overseas territories regarding the "critical" issues of tax information exchange and beneficial ownership, a practice which uses a nominal third-party resident in a low-tax state to shield income from taxation.

"As you know, I have made fighting the scourge of tax evasion and aggressive tax avoidance a priority for the G8 Summit which the UK is hosting next month," he wrote.

"With one month to go, this is the critical moment to get our own houses in order.

"I am looking to all the Overseas Territories and Crown Dependencies to continue to work in partnership with the UK in taking the lead on two critical issues: tax information exchange and beneficial ownership," he added.

The Conservative leader said he respected the right to be a lower-tax jurisdiction, but added the British government needed to know "who really owns and controls each and every company.

"This goes right to the heart of the ambition of Britain's G8 to knock down the walls of company secrecy," he stressed.

Cameron sent the letter to the leaders of Bermuda, British Virgin Islands, Cayman Islands, Gibraltar, Anguilla, Montserrat, Turks and Caicos Islands, Jersey, Guernsey and the Isle of Man.

The United States, Britain and Australia earlier this month announced a joint effort to expose tax dodgers with an investigation of a massive cache of bank account data from tax havens that was leaked to the authorities.

The three countries said they are sharing the huge trove of data on accounts in Singapore, the British Virgin Islands, the Cayman Islands and the Cook Islands, which includes names of account holders and their advisers.