The first campaign targeted accounts in big UK banks in places like Guernsey
A new campaign to squeeze tens of millions of pounds in unpaid tax from people with offshore bank accounts has been launched by the government.
HM Revenue & Customs (HMRC) used the 2009 Budget to announce a new "offshore disclosure opportunity".
It will run until March 2010 and prompt people with money in offshore accounts to confess if they have failed to pay any tax on their interest.
The Revenue's first campaign in 2007 raised £450m from 45,000 people.
That targeted offshore accounts held by the UK's big High Street banks.
Last year, the HMRC said its second campaign would be aimed at 300 or so smaller banks and building societies which also have offshore operations.
The HMRC's efforts followed a legal breakthrough which gave it the power to demand that banks reveal the identify of all their UK citizens with accounts held abroad.
Since then the government has stepped up its efforts to stop international tax dodging.
The HMRC has been investigating about 300 rich Britons who have failed to pay an estimated £300m in tax on more than £1bn in Liechtenstein bank accounts.
More recently it has signed agreements with tax havens such as Jersey, Guernsey, Isle of Man, and the British Virgin Islands to allow the exchange of financial information on UK residents.
"This is in line with the coordinated international approach being taken towards such bank accounts as outlined at the recent G20 summit meeting," said Ronnie Ludwig of accountants Saffery Champness.
"Following the G20 summit the world has become a much smaller place for tax evaders.
"The knowledge that they are much more likely to be caught than was ever the case before should provoke some more meaningful results from the latest disclosure opportunity," he added.