Thieves have stolen a server from a forensics company in Kent. The server contains a database of highly confidential telephone records for use in police investigations.

In an official statement, Forensic Telecommunication Services (FTS) confirmed that it was recently the victim of a break-in and that among the equipment stolen was a server containing some case files pertaining to FTS' forensic work for government authorities.

FTS specialises in recovering data from mobile devices and telecommunications equipment, particularly for use as evidence in criminal cases.

The company, whose clients include Scotland Yard and the Crown Prosecution Service, has assured the public that the server is security protected and the breach will not compromise any ongoing police operations.

The news comes just days after a similar attack in which thieves broke into the Manchester office of First Response Finance and specifically targeted servers that held the financial details of customers, suppliers and staff.

Although FTS has stated that the only information on the server is made up of old cases or ongoing cases that are subject to full disclosure to both defence and prosecution teams, the theft has sparked major security concerns.

"This is extremely serious. Terror investigations are extremely complex and depend on vital intelligence and evidence based on phone records," said Shadow Home Secretary David Davis.

"While we have to let the police get on with their investigation, it is essential that the government take every possible step to protect this information and leave absolutely nothing to chance."

"We are keeping an open mind at this stage as to the motive behind the burglary," added Adrian Leppard, Kent assistant chief constable.

"However, we and the company have informed other police forces. Our understanding is that almost all information on the stolen computer equipment relates to cases where the evidence has already been disclosed to defence solicitors."

"In any case, the immediate disclosure and swift action taken by the FTS following the breach is yet another positive indication that organisations are beginning to take data protection seriously."

All the data was restored from backups within 24 hours.

As a result of this incident FTS has said it will be "undertaking a full and comprehensive review of security across the whole company."