All data about UK call, text, email and internet use could be handled by a private firm in an effort to cut costs, sparking fears that the information could eventually be leaked.

Home secretary Jacqui Smith is set to publish a consultation paper on the subject next month containing a key option over the proposed handover of the scheme to the private sector.

Currently telecommunications firms store all the data, which can be obtained by the authorities as evidence in crime investigation. But the Government wants a unified database containing all the tracking information to speed up the process.

Worries the scheme could cost up to £12 billion has led to exploration of alternative options, and the move to a private company could be the answer. The plan also includes tough locks and assurances on database to ensure that the information never falls into the wrong hands.

Compromised

However Sir Ken Macdonald, former director of public prosecutions (DPP), told the Guardian it would only be a matter of time before the database was compromised.

"Authorisations for access might be written into statute. The most senior ministers and officials might be designated as scrutineers. But none of this means anything," Macdonald said to the Guardian.

"All history tells us that reassurances like these are worthless in the long run. In the first security crisis the locks would loosen."

"It is a process which can save lives and bring criminals to justice. But no other country is considering such a drastic step. This database would be an unimaginable hell-house of personal private information," he added.