Sir David Clementi, chairman of Prudential, rejected a shareholder's assertion at yesterday's annual meeting that his decision to sack Jonathan Bloomer as chief executive was a " murky assassination" instigated by powerful City institutions.

"We did not come under severe institutional pressure," Sir David said. "The decision was a forward-looking one, not a judgment on the past."

Mr Bloomer did not formally resign until yesterday's meeting was over and received a long round of applause after telling shareholders he was "disappointed" to be leaving after ten years with the company.

"We have come a long way and I am leaving the group in good shape and with a great team," he declared.

Mr Bloomer was forced out in late March. Earlier, institutional investors had objected to a surprise move last year to raise £1 billion from shareholders in a rights issue after the dividend had been cut in 2003.

Some also criticised Mr Bloomer's failure to find a buyer willing to pay an acceptable price for Prudential's majority stake in the Internet bank Egg and his decision to drive for expansion in the UK when he had previously made growth in Asia his strategic priority.

But Sir David, a former deputy governor of the Bank of England, paid tribute to Mr Bloomer for steering Prudential through "the severest market the insurance sector has experienced".

"He leaves the group a much more focused business and in much better shape than when he took over five years ago," he said. But he added: "It was the board's decision that Mark Tucker was the right man to take us forward to the next phase of our growth and it was the right decision."

Mr Tucker takes over as chief executive this morning. He rejoins after an absence of less than two years after leaving to become finance director of HBOS, the merged Halifax and Bank of Scotland.

He had previously worked for 17 years at Prudential, where he built up its Asian operation, at one time identified by Mr Bloomer as the group's most promising source of future growth.

In his final address to Prudential shareholders, Mr Bloomer sounded a defiant note, saying the proceeds of the rights issue were needed to shore up the group's capital base as it pursued growth opportunities in the UK.

"The rights issue was certainly the right thing to do," he insisted. Two months ago, many of Mr Bloomer's critics were mollified when the company reported a spectacular recovery in full-year profits and his abrupt dismissal came as a surprise.

Sir David signalled that there would be little shortterm change in strategy under Mr Tucker. Prudential would continue to devote equal emphasis to the US, Asia and the UK, and was sticking by its plan to restore the annual dividend "over time".

While directors continued to regard the stake in Egg as "non-core", they would ensure it is managed to "deliver value to our shareholders". But private shareholder David Farmer accused Sir David of inconsistency, describing Mr Bloomer's exit as 'a murky assassination'.