A major security alert has been sparked after the theft of a computer database containing thousands of top secret telephone records from police investigations into terrorism and organised crime.

Worried police chiefs throughout the UK launched a massive inquiry into the removal of the sophisticated computer and other IT equipment from a private firm specialising in gathering evidence from mobile phone calls made by suspects. SO15, Scotland Yard's elite Counter Terrorism Command, was immediately alerted. The raid at the high-security head office of Forensic Telecommunication Services Ltd (FTS) at Sevenoaks, Kent, raised fears that vital evidence from undercover investigations may have been lost or have fallen into the wrong hands.The theft of such sensitive data will reopen the debate about whether private companies should be employed to carry out crucial security or Government work under contract. The stolen computer server - a metal box the size of a large DVD player - contained details of who made calls on mobiles, their exact location and precisely when the calls were made.