£24m: The cost of tracking your emails and phone calls

The Home Office has revealed the multimillion-pound cost of monitoring the UK's communications.

Home Office policing and security minister, David Hanson, told Parliament last week that millions are now being spent to fund ISPs', telcos' and mobile operators' retention of communications data under the European Data Retention Directive and Anti-Terrorism Crime and Security Act 2001 (ATCSA) code of practice on data retention.

Data retained under the legislation includes the details of the duration, destination and location of electronic communications, although not details of their content. The data retention legislation has proved unpopular with civil liberties groups who view it as an infringement of privacy.

According to Hanson, the cost of "sponsor[ing] systems to enable communications service providers to store communications data" over the last five years has topped £24m.

For 2008-2009, the Home Office spent £3.6m funding retention under the ATCSA, and £6.6m under the European Data Retention Directive (EUDRD).

The figure represents a significant year-on-year fall for ATCSA retention, with the 2007-2008 costs hitting £5.7m. In contrast, the amount spent on retention as a result of the EUDRD increased substantially from the 2007-2008 figure of £2.6m.