Under-fire Cameron announces Panama Papers taskforce

The force will be led by the HMRC tax authority and the National Crime Agency, but is unlikely to spare Cameron from more scrutiny over his admission Thursday that he bought and then sold shares in his late father's Bahamas-based offshore fund.

Cameron at first refused to comment on his father's fund, details of which emerged in the leak of documents from Panama law firm Mossack Fonseca, and admitted Saturday he had mishandled the controversy.

The prime minister was to insist Sunday that Britain has been at the "forefront of international action to tackle aggressive tax avoidance and evasion," according to a statement from the finance department, but the latest revelations appear to have undermined his claims to be leading the efforts.

A Yougov poll released Thursday showed that Cameron was the second least trusted British politician on tax affairs, coming behind only his finance minister George Osborne.

The taskforce will investigate the leaked files to identify clients of the Panama firm suspected of money laundering and tax evasion, and will have a £10-million ($14-million, 12-million-euro) budget.

"There is clearly further to go and this taskforce will bring together the best of British expertise to deal with any wrongdoing relating to the Panama Papers," said Cameron.

The taskforce will report its findings "later this year", according to the statement.

READ: Panama Papers: Tax scandal weakens Cameron ahead of EU referendum

Cameron said he would publish his tax returns and shouldered the blame for the row.

He earlier admitted he and his wife had held a stake in his father's Blairmore Holdings scheme. They bought the stake for £12,497 in 1997 and sold it for £31,500, four months before he became prime minister in 2010.

He is believed to have paid tax on the dividends paid out by the trust, but not on the profits when sold.

"It has not been a great week. I know that I should have handled this better, I could have handled this better," he told his Conservative Party's spring forum in London on Saturday.