Mr Bloomer, until now the group's pounds 476,000-a-year finance director, will take over the chief executive job next May when Sir Peter Davis, the current chief executive featured on television as "the Man from the Pru", moves up to become chairman.
Sir Martin Jacomb, aged 69, will step down as non-executive chairman next May after five years in the post. Sir Peter, in charge of the group throughout a turbulent four years since 1995, will be an executive chairman.
City analysts were yesterday surprised by the timing of the announcement. Some suggested that Sir Martin's replacement with Sir Peter suggested that a big tie-up with another large financial group was now unlikely.
"There was a common theory that Sir Martin was there in case of a big merger because, owing to his age, he might be happy to retire. Now it looks like the deals are off," said one.
Prudential was last year linked to National Westminster Bank. It has also been linked to the Halifax, the Norwich Union and a string of large high street financial groups. However, it recently said it would instead expand through Egg, the telebank which has attracted pounds 5bn in the six months since its launch.
Mr Bloomer, who became deputy chief executive yesterday, said the appointment had been made a year in advance to give the group time to look for a finance director - without causing too many questions to be asked.
In contrast to recent public statements, he held open the possibility of a link-up with a large financial services rival. "When you look at the changes taking place in retail financial services it might be at some point sensible to consider merging with someone large if that created shareholder value. Given the changes, that might be a real issue - it isn't now but may well be at some point," he said.