The government's eavesdropping watchdog has issued its latest report, revealing there were more than 253,000 requests to intercept individuals' communications in the last nine months of 2006, including 1,694 requests by local authorities.
This compares to nearly 439,000 requests between 1 January, 2005 and 31 March, 2006.
Hundreds of UK public bodies are authorised to intercept individuals' communications, including the Ambulance Service and fire authorities, British Transport Police, HM Revenue & Customs, Secret Intelligence Service, Security Service, Serious Fraud Office, Serious Organised Crime Agency, 474 local authorities and 52 police forces.
Local authorities are restricted to acquiring communications data for crime-prevention and detection purposes. The agencies most commonly requesting data at this level are the Trading Standards Service, Environmental Control and the housing benefits department, according to the report.
In the report, which covers the period from 11 April, 2006 to 31 December, 2006, Sir Paul Kennedy, the interception of communications commissioner, stated: "This highly intrusive investigative tool" has "contributed to a number of striking successes" in combating crime and terrorism.
Kennedy wrote: "It has played a key role in numerous operations, including, for example, the prevention of murders; tackling large-scale drug importations; evasion of excise duty; people smuggling; gathering intelligence, both within the UK and overseas, on terrorist and various extremist organisations; confiscation of firearms; serious violent crime; and terrorism."
The report reveals 24 interception errors were reported in the last nine months of 2006, where data from the wrong person was intercepted. This is "a significant decrease" on the figure in the previous report, according to Kennedy, but, he added: "I still consider the number of errors to be too high."
There were also 1,088 acquisition and disclosure errors reported — for example, intercepting billing information such as the phone numbers a person has called — representing about 0.4 percent of the total number of requests, according to the report.
All errors were caused by human or procedural error or by technical problems, said the report — a common problem being digits in phone numbers being transposed by mistake.
Despite the mistakes and the controversial nature of eavesdropping on private communications, Kennedy was upbeat about its role in tackling crime.
"It is my view that, during 2006, interception played a vital part in the battle against terrorism and serious crime, and one that would have not been achieved by other means. I am satisfied that the intelligence and law-enforcement agencies carry out this task diligently and in accordance with the law," stated Kennedy.
The commissioner did not, however, give his backing to intercepted communications being used as evidence in court. He wrote: "At present, I am firmly of the opinion that the benefits of any change in the law are heavily outweighed by the disadvantages." He added that the public will need to be convinced of its benefits before any move to change the law.