By Jonathan Davies

The chairman and chief executive of HSBC will face questioning by MPs today (Wednesday) over the recent tax scandal.

MPs of the Treasury Select Committee will question HSBC chairman Douglas Flint and the bank's chief executive Stuart Gulliver.

Earlier this month, HSBC published a full apology after a BBC Panorama documentary accused the bank of helping hundreds of customers to avoid paying tax by using its business in Switzerland.

The chairman of the Treasury Committee Andrew Tyrie said: "The Committee is concerned about allegations involving HSBC and its Swiss private bank.

"Banks have repeatedly told the Committee that, since the crisis, they have put in place reforms to ensure that they operate on the basis of sharply improved standards.

"The Committee will need reassurance that they have done so in private banking."

On Monday, former public prosecutor Lord Ken Macdonald said the bank had left itself open for criminal charges.

n a legal opinion prepared for consumer group SumOfUs, Lord Macdonald said: "It seems clear, from the evidence we have seen, that there exists credible evidence that HSBC Swiss and/or its employees have engaged over many years in systematic and profitable collusion in serious criminal activity against the exchequers of a number of countries.

"The corporate and wholesale nature of HSBC Swiss's apparent involvement in what amounts to grave cross border crime makes it all the more obvious that the relevant evidence, once it came the attention of HMRC, should have been the subject of urgent and sustained criminal investigation."