Shares in alternative carriers rallied after Colt Telecom said Fidelity, the fund manager that owns 48% of the network provider, would take majority control and ensure it raised at least £400m (€637m).

Fidelity will underwrite a rights issue in Colt stock, and has undertaken to buy enough shares to increase its stake to 54%. If all other shareholders take up their rights to new stock, this will mean issuing another £116m, taking the total offer to £516m.