London (AFP) - British opposition leader Ed Miliband went on the offensive on Wednesday over an international scandal involving London-based HSBC bank, accusing Prime Minister David Cameron of being soft on tax avoidance.

Miliband attacked Cameron as "a dodgy prime minister" and homed in on Stephen Green, the former chief executive and chairman of HSBC who later became a trade minister under Cameron and was made a Lord.

"Can the prime minister explain the revolving door between Tory party HQ and the Swiss branch of HSBC?" Miliband asked in a heated exchange during prime minister's question time, a weekly parliament debate.

"Does the prime minister expect us to believe that in the three years Stephen Green was a minister, he never had a conversation with him about what was going on at HSBC?"

The scandal over leaked files revealing HSBC's Swiss account holders has erupted ahead of a general election in May, sparking a furious blame game between Cameron's Conservatives and Labour.

Cameron has hit back saying that Labour was in power at the time the files were first brought to the attention of French tax authorities in 2007 and accusing Labour of having close ties to Green.

"No government has been tougher than this one in chasing down tax evasion and tax avoidance," the prime minister said, pointing to thousands of tax prosecutions since he came to power in 2010.

Green himself, a Church of England clergyman who published a book on banking ethics, has declined to comment but is now under pressure to testify before a parliamentary committee.

Labour's Margaret Hodge, the head of the committee, has promised a full inquiry, saying the revelations show "a secretive global industry serving a wealthy elite".

HSBC's Swiss banking arm has insisted it has undergone a "radical transformation" since the initial revelations and now has "strong compliance controls in place".





- 'Friends of the tax dodgers' -





The head of HMRC Lin Homer was shouted down by lawmakers as she tried to defend the tax authority's record in parliament.

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MPs have accused the agency of not cracking down hard enough on tax evaders after French authorities shared information with them in 2010.

Authorities say they have pursued about 1,100 people and recovered Â£135 million ($206 million, 181 million euros), while one person was prosecuted.

"We were speedy and on the case," Homer said.

But her remarks were undermined by an interview released later with whistleblower Herve Falciani, who stole the data as an HSBC employee and gave it to authorities.

Falciani told an interview with Sky News he had tried to alert British tax authorities in 2008 to no avail.

"I sent a mail, a very naive email in 2008, to England, to the department dedicated to tax evasion. Afterwards I even called them," Falciani said.

The rival Labour and Conservative parties, which are neck-and-neck in polls, have blamed each other for the scandal.

Labour leader Miliband attacked Cameron over a report in the Guardian newspaper that seven Conservative donors were among the HSBC Swiss account holders.

"He can't get away from it, he's a dodgy prime minister surrounded by dodgy donors," Miliband said.

Cameron hit back, saying Miliband and his shadow finance minister were "friend of the tax dodgers" during the previous Labour government.

The cache of files made public in the so-called SwissLeaks case includes the names of celebrities, alleged arms dealers and politicians -- though inclusion on the list does not necessarily imply wrongdoing.

Published at the weekend, the files claim HSBC's Swiss division helped clients in more than 200 countries evade taxes on accounts containing $119 billion (104 billion euros).

Several countries, though not Britain, have launched investigations into HSBC in recent years following the revelations.