When Andy Hornby was elevated to the helm of HBOS less than two years ago, he was hailed by many as the wonder boy of British banking. At 39, he was the youngest chief executive of a British bank and one of the youngest bosses of a FTSE 100 company.

The past few months have no doubt left Mr Hornby, now 41, feeling older than his years and that his position as head of Britain's biggest mortgage lender is vulnerable.

In March, he was forced to deny malicious market rumours that claimed that HBOS was seeking emergency funding from the Bank of England. In April, he announced £2.8 billion of treasury losses and a £4 billion rights issue. He hopes to prove market fears that the shares will not be taken up in the coming month are unfounded.

Mr Hornby's non-banking background - he joined HBOS from Asda - was also highlighted last year when it was suggested that after the Northern Rock crisis the FSA may tighten criteria for those in senior positions at banks.

There is no question that Mr Hornby's aptitude for banking is facing its toughest test as HBOS tries to maintain investor and customer confidence. HBOS shares are among the worst-performing bank stocks after halving since the credit crunch took hold last autumn.

Mr Hornby has the seemingly unwavering support of Lord Stevenson of Coddenham, the HBOS chairman, who recently described Mr Hornby as a “hell of a tough guy” who was positioning the group well in the context of the credit crisis. Mr Hornby wants to be judged in three years' time, when, he says, the rights issue would be vindicated.

After studying English at Oxford University and qualifying at the top of his MBA class of 800 at Harvard, Mr Hornby spent the first years of his career with Blue Circle, the building products company, and Boston Consulting, the management adviser. After three years with Asda, his break into banking came in 1999 when Halifax made him head of its retail before Halifax merged with Bank of Scotland. He made an impact by masterminding Halifax's infamous attacks on the “big four” high street banks: Lloyds TSB, Royal Bank of Scotland/NatWest, Barclays and HSBC.

Preparation for the top job began in July 2005, when he was made chief operating officer. Later it emerged that he had received a special bonus scheme worth £2 million to stop him being poached by Boots as chief executive.