A story claiming that helped thousands of wealthy UK clients dodge taxes via Swiss private bank accounts relates to events happening before major changes in 2008, the bank has stated.

A BBC Panorama documentary described how it had “seen thousands of accounts from HSBC's private bank in Switzerland leaked by a whistleblower in 2007. They show bankers helped clients evade tax and offered deals to help tax dodgers stay ahead of the law.”

Such a report adds to a drumbeat of media and political controversy over the role of firms providing offshore banking facilities, although in recent years American, UK and other banking groups have had to significantly change direction in the face of mounting criticism. A number these banks, such as HSBC itself, have suffered theft of client data. The BBC report mentioned how documents, stolen by a computer specialist working at HSBC, contained details of more than 100,000 clients worldwide.

"HSBC's Swiss private bank began a radical transformation in 2008 to prevent its services from being used to evade taxes or launder money. New senior management have comprehensively overhauled the business, including closing the accounts of clients who did not meet our high standards and ensuring we have strong compliance controls in place,” Franco Morra, chief executive, Private Bank Switzerland, said in a statement emailed to WealthBriefing over the weekend.

“We have no appetite for business with clients or potential clients who do not meet our financial crime compliance standards. These disclosures about historical business practices are a reminder that the old business model of Swiss private banking is no longer acceptable,” Morra said.

In December last year, it was reported that Swiss authorities had charged a former computer analyst at the private bank of HSBC in Geneva with industrial espionage and breach of secrecy laws. Herve Falciani reportedly gave prosecutors in France and Spain data on thousands of Swiss bank accounts. He has previously told the media that he is a whistleblower trying to help governments track down citizens who used accounts in Switzerland to evade paying tax. But Switzerland's attorney general, which did not identify Falciani by name, has said that Falciani tried to profit from the data. It accused him of trying to sell the information to banks in Lebanon.

HSBC’s private banking activities have been the subject of negative media reports for some time. The Swiss private banking part of the firm has been charged by a Belgian court with tax fraud and money laundering after being accused of helping wealthy customers avoid tax, costing hundreds of millions of euros in unpaid taxes. Prosecutors allege that the bank helped hundreds of clients, including diamond dealers in Antwerp, move money to tax havens located mainly in Panama and the British Virgin Islands. HSBC says it is co-operating with investigations. Meanwhile, Argentina’s tax agency has charged HSBC for helping more than 4,000 clients evade taxes by hiding their money away in secret Swiss bank accounts.

As far as the leaked data from HSBC’s Swiss private bank in Geneva is concerned, the BBC report said HM Revenue and Customs, the UK tax authority, was given the leaked data in 2010 and has identified 1,100 people who had not paid their taxes. But almost five years later, only one tax evader has been prosecuted. HMRC said £135 million ($205 million) in tax, interest and penalties have now been paid by those who hid their assets in Switzerland.

"The HSBC case is quite different from other recent tax scandals. HSBC has been complicit in clear tax evasion and law breaking rather than legitimate tax avoidance,” Professor Crawford Spence, of Warwick Business School, told this publication.

“The latest details to emerge from the Public Accounts Committee are also particularly damning for the UK tax authorities, HMRC,” he continued. “It appears that we need to rely on computer hackers, investigative journalists and corporate whistleblowers to expose tax evasion. HMRC should be doing this as a matter of course, but must be lacking either in resources, political will or both,” he added.

The UK and Switzerland have signed a bilateral agreement under which Britons with undeclared accounts in the Alpine state can declare this money and, depending on the speed of compliance, incur certain penalties.

Meanwhile, the US and Switzerland in 2013 signed an accord under which Swiss banks have the option to state if they think they do, or do not, have the risk of undeclared money.