The chairman of Prudential, the UK's second largest insurer, is to step down following criticism of his former involvement in struggling telecoms firm Marconi.

Sir Roger Hurn was chairman of Marconi until September 2001, when he resigned after the company announced a first quarter operating loss of �227m, leading to a nose-dive in its stock market value and the loss of thousands of jobs.

He became chairman of Prudential two years ago, but has been hit by public criticism of his role in Marconi's fall from grace.

Announcing his resignation, Sir Roger said: "I am concerned that the company should not be adversely affected in any way by my recent involvement with Marconi.

Spectacular fall

"Because of Prudential's role as a significant investor in major British companies and hence its influence on corporate governance, I have decided that it is in Prudential's best interests for me to resign from the chairmanship and board."

Marconi's fall from a share price high of �12.50 to its current 6.65p is one of the most spectacular in UK corporate history.

The decision to sell off the company's defence assets and buy up telecoms firms hit Marconi hard as the telecoms bubble burst.