The group has been linked with takeover approaches from Bank of China, Macquarie and GFI - with whom it failed to consummate a merger in 2008.

In a note to investors, James Hamilton of Numis Securities said a more likely candidate for a bid would be an exchange.

"We believe the most likely acquirer to be an exchange which could share IT costs and where Tullett would provide a complementary product set. Exchanges command a substantial premium valuation and consequently even with a significant bid premium and modest cost synergies such a deal would be expected to be enhancing."

Tullett Prebon shares moved up 16.7% on the news to 362p, valuing the business at £779m