Public authorities made 519,260 requests for communications data in 2007, an annualised increase of more than 50 percent.
The figure was published in the annual report of the interception of communications commissioner Sir Paul Kennedy. In the last nine months of 2006, he said that 253,557 requests for communications data were made to communication service providers, and last year's figure was 54 percent higher on an annualised basis.
Communications data includes email headers, telephone billing data and the location of mobile telephones, but not the contents of communications.
Kennedy did not provide a breakdown of which authorities made the requests. "I can say that the intelligence agencies, police forces and other law-enforcement agencies are the principal users of communications data," he said.
However, he added that local authorities, which have been criticised for using surveillance powers to investigate parents lying about their home address for the purposes of school admissions, accounted for just 0.3 percent of all requests.
"Any suggestion that a low-ranking council employee may have unrestricted access to the telephone records of a member of the public is far removed from reality", due to approval having to be sought from a senior official, Kennnedy said. During 2007, 154 councils used their powers, making 1,707 requests — "the vast majority for basic subscriber records", with very few asking for itemised call records.
"Generally, local authorities could make much more use of communications data as a powerful tool to investigate crime," said Kennedy. However, he added that, of the inspections of 44 local authorities last year, two were re-inspections because "the level of compliance was not as good as it should have been".
The commissioner said that 1,182 errors were reported by public authorities in accessing this data, with two-thirds made by those authorities and one third by communication services providers. However, the reporting system changed in October, so only errors which result in an intrusion on an innocent third party are now reported; there were 99 instances of this in the last three months of 2007.
The report added that increasing numbers of police forces are introducing automated systems for managing requests for communications data, and "these will inevitably reduce the number of keying errors which occur".
Kennedy also reported that the total number of warrants for the interception of communications, such as tapping telephone calls, rose 20 percent, from 797 at the end of 2006 to 957 at the end of last year, although those approved by the Scottish Executive dropped from 43 to 28.
He said that the number of errors and breaches of interception was "too high" in 2007, at 24 reported cases, although the trend appears to be falling: the same number of cases were reported between April and December 2006. Security service MI5 reported eight errors, GCHQ six, communications service providers five, the Police Service of Northern Ireland four and HM Revenue & Customs one.
GCHQ's errors, which were typical of those made by other organisations, included: an analyst mistyping a telephone number into a targeting database, although no calls were intercepted as a result; a wrong line being intercepted during "a fast-paced incident"; and two lines being tapped after surveillance was meant to end, due to a problem with software that has since been improved.
