Stuart Gulliver, HSBC's chief executive, reportedly kept millions of his own money sheltered in the bank’s private Swiss offshoot.

The Guardian says Mr Gulliver - who announced the bank’s full-year results this morning, which showed a 17% fall in pre-tax profits last year - kept $7.6m (around €6.72m) via an account held by a Panamanian company.

Leaked files reportedly show that in 2007 he was the beneficial owner of an account held by Worcester Equities Inc.

It comes amid the ongoing scandal over claims HSBC's Swiss private banking arm helped wealthy clients evade and avoid tax, and provided services to criminals including arms dealers.

The Derby-born banking chief apologised for the behaviour of the Swiss division in national newspaper advertisements last week.

Mr Gulliver insisted it had been "completely overhauled" since 2007, when whistleblower Herve Falciani opened the door to the scandal, stealing company data and passing it to French authorities.

Swiss prosecutors have launched a criminal investigation into allegations of money laundering after raiding the bank's offices in Geneva.

The 55-year-old - believed to have raked in a £7.4m (€10m) reward package last year - is legally domiciled in Hong Kong after working there for many years, despite now working in the UK.

Representatives for the banking boss told the Guardian he had paid his bonus payments into HSBC Suisse until 2003.

They said Hong Kong tax had been paid and that Mr Gulliver had also told the UK taxman about the account a "number of years" ago.

HSBC added: "Full UK tax has been paid on the entirety of his worldwide earnings less a credit for tax paid additionally in Hong Kong.

"The Swiss account was set up in 1998 in the name of a Panamanian company for reasons of confidentiality and this had no other purpose and provided no tax or other advantage."

MPs are set to grill HMRC tax officials on Wednesday over accusations they failed to act properly on the leaked files and potential evidence of tax evasion by more than 3,000 Britons.