UK authorities increased the number of requests they made about the public's use of texts, emails and other communications data last year, an official report has revealed.
It said there were more than 570,000 demands made in 2012.
The report also revealed that mistakes made while using the information led to six members of the public being wrongly detained or accused of a crime.
It said all these cases had involved internet data.
A further error resulted in the police visiting the wrong address while looking for a child who had threatened to harm themselves.
"Fortunately errors with such severe consequences are rare," the report added.
The document also noted that the authorities might make several requests in the course of a single investigation, so the headline figures do not equate to the number of individuals or addresses targeted.
The Interception of Communications Commissioner's report revealed that a total of 3,372 lawful intercept warrants were issued in 2012.
These are needed if police and intelligence officers want to acquire the contents of an email, telephone call or text message.
This reflected a 16% rise on 2011. The commissioner, Sir Paul Kennedy, added that he was aware of 55 related errors or breaches.
These included officers not having been granted the necessary permissions before intercepting the data; mistakes which led to the wrong data being obtained; and errors made when the data was being copied.
Officials made a further 570,135 requests for information about who was involved in communications, when they were made and where they happened.
The name of an email account holder and the time and date of a person's telephone calls are included in this group.
The report said there were a total of 979 mistakes made involving these kinds of requests.
Sir Paul said that approximately 80% were the fault of public authorities and 20% were caused by the networks that provided the phone and internet data.
Although the police and intelligence services accounted for the bulk of these queries, local authorities could also ask for data to identify criminals who had avoided paying taxes, illegally dumped waste, sold counterfeit goods or otherwise preyed on vulnerable members of the community.
The report said 160 local authorities across the UK made a total of 2,605 requests.
Sir Paul noted that the overall rise in the number of requests was "unsurprising considering the fact that the UK hosted the Olympic and Paralympic Games in 2012 and that communications data supported a number of operations undertaken to ensure the Games were safe".
Other highlighted examples of where the intercepts had been useful included one case in which location data taken from the account of a suspected Post Office robber linked him both to the incident and the theft of a car the previous day.
In another case, police were able to identify a thief who had been stealing equipment and supplies from an NHS Scotland hospital. They did this by acquiring data associated with the internet and email addresses used when the criminal tried to sell them online.
"Many of the largest drug-trafficking, excise evasion, people-trafficking, counter-terrorism and wider national security, and serious crime investigative successes of the recent past have in some way involved the use of interception and/or communications data," Sir Paul concluded.
However, privacy rights campaigners have concerns.
"The idea that one commissioner with a handful of staff can meaningfully scrutinise 570,000 surveillance requests is laughable," said Nick Pickles, director of Big Brother Watch.
"The commissioner continues to refuse to even say how many applications he inspected, which only reaffirms how unconvincing his assurances are.
"If the public are to have confidence that these powers are being used properly our entire surveillance regime, devised before Facebook even existed, is in need of a total overhaul to bring it in line with modern technology and to ensure people's privacy is not intruded upon either without good reason or by mistake."