CSFB's key deal maker Nelson is leaving the City after 30 years

John Nelson is to step down as head of investment banking at Credit Suisse First Boston at the end of March, in a move that will bring the curtain down on one of the most colourful careers in investment banking.

Mr Nelson, 55, advised Railtrack during the events that led up to its recent administration, and is best known for advising Granada on its acrimonious takeover of the Forte hotels chain. A former vice chairman of the Lazard investment banking partnership and a leading banker at Kleinwort Benson, he also brokered Barclays' acquisition of the Woolwich building society.

"I have decided that after over 30 years in investment banking, the time is right for me to make a complete change," Mr Nelson told staff in an e-mail circulated yesterday. "Now that I am in my mid-fifties, I do not want to miss the opportunity to do other things in business. I am also fortunate in having a number of interests outside business, on which I fully intend to spend more time."

Mr Nelson is thought to have told John Mack, CSFB's chief executive since July, of his intention to retire within the last week. His decision was influenced by the forthcoming introduction of the Financial Services Authority's new regulatory regime at the end of November, for which he has prepared CSFB since his arrival in 1998. Mr Mack had wanted him to play a larger role in the bank, which has been restructuring amid the downturn in corporate advisory work.

It is likely that Mr Nelson will take up a variety of non-executive posts and pursue long-standing interests in sailing and the arts. He is not expected to return to investment banking.

Handling the first privatisations of the Thatcher government was the highlight of his career, he said.