David Cameron has defended his Government's record on tackling tax evasion, after senior politicians and HM Revenue & Customs were accused of failing to act over claims that HSBC helped clients dodge payments totalling millions of pounds.
A furious blame game was under way between the Tories and Labour after a huge trove of files on secret Swiss accounts run by the bank was leaked.
The documents have already sparked criminal probes in several countries and attempts to claw back cash after being stolen by an IT worker in 2007 and passed to French authorities.
Now the details of 30,000 accounts holding almost £78bn of assets are being revealed after they were obtained by a French newspaper and analysed by a team of investigative journalists.
They are reported - by BBC's Panorama and the Guardian - to include evidence that the bank colluded with some clients to hide accounts from tax authorities in their home countries.
Among those alleged to have been exposed as having accounts with the Swiss arm of HSBC are said to be politicians, sports stars and celebrities as well as criminals and traffickers. According to the Irish Times, the list includes well-known Irish businesspeople and Dublin-based investment funds.
Treasury minister David Gauke was called to the House of Commons to answer an urgent question from Labour about the official response to the leaked documents and Mr Cameron's decision in 2010 to appoint former HSBC boss Stephen Green to his Government as trade minister - a position he held until 2013.
But the Tories hit back pointing out that Ed Balls had been city minister in the period when tax evasion had been taking place.
Mr Cameron said: "Stephen Green was an excellent trade minister. But I'd also add no Government has done more than this one to crackdown on tax evasion and aggressive tax avoidance.
"I put it at the head of my G8 agenda, to make sure there's more tax transparency, the big firms pay proper taxes and we raise money from people previously evading and avoiding tax and will go on doing that as a Government."