Shares in St James's Place tumbled more than 10 per cent after the wealth manager failed to persuade the market that changes in the Budget will not lead to a drop in sales.

Chancellor Alistair Darling last week unveiled plans to increase the tax burden on those earning more than £150,000 a year - some of whom will be SJP clients.

Analysts fear that these high earners will pay less money into pensions in future given the tax grab, potentially hurting the insurer and fund manager.

Chief executive David Bellamy claimed the Budget would be "neutral" but Numis Securities responded: "We remain unconvinced."

The shares lost 17½p to 146½p. Sentiment towards the group was not helped by first-quarter sales figures, which fell 5% to £94 million. Funds under management slipped 6% to £15.3 billion.

SJP is 60%-owned by Lloyds Banking Group - another source of uncertainty.

It is assumed by sector watchers that this stake is up for sale, though it is not a priority for either management team to resolve. Lloyds acquired the holding when it took over HBOS last year.