The past 15 months have been, according to Sir Win Bischoff, “not the easiest of my 44 years in banking”.

One of the few Europeans to reach the highest ranks of Wall Street, when he was appointed chairman of Citigroup in December 2007, he left under the biggest of clouds in January after an $18.7 billion (£12.7 billion) net loss in 2008, with $8.29 billion in the fourth quarter.

Such was the anger directed at Sir Win and Citigroup’s other directors that one investor told them at the annual meeting last Wednesday: “Never before have so few done so much damage to so many as we have had here at Citigroup.”

The next 15 months or more may prove equally taxing to Sir Win, 68, who has dual British and German citizenship.

He is reported to have been asked by Alistair Darling to consider taking the helm at UK Financial Investments (UKFI), the Treasury body that holds the taxpayer’s stakes in some of Britain’s largest banks.

If he takes the job, the former Schroders chairman must deal with Northern Rock’s toxic loans, which are to be hived off into a “bad bank” controlled by the Government after a sale of the bank by the end of the year. Whoever becomes UKFI chairman will replace Glen Moreno, the chairman of Pearson, the media and education group.

Described as charming and one of the “the world’s best-connected businessmen”, Sir Win became Citigroup chairman in the wake of the forced exit of Charles Prince.

His appointment was a surprise. Sir Win was little-known on Wall Street and had no hands-on experience of capital market trading. Critics questioned whether he was the right choice to steer Citigroup through a time of turmoil.

After the bank’s performance in 2008, in which its share price fell by 77 per cent, the board put some of the responsibility on Sir Win and replaced him with Dick Parsons, a former Time Warner chief executive.

Born in 1941 in Aachen, Germany, Sir Win moved to South Africa in 1955 and graduated from the University of Witwatersrand, Johannesburg. He joined Citigroup in 2000 after the bank bought Schroders, where he was chairman and had worked since 1966.

He became chairman of Citigroup Europe in 2000, the year he was knighted, and in 2005 helped to steer the bank’s purchase of Egg, the credit card company.

He has homes in London, Gloucestershire and Italy and enjoys opera and golf.