Police insist they can justify every use of covert surveillance tactics allowing the capture of more than 6,500 pieces of private communications data in a year.

Suffolk and Norfolk police intercepted 6,654 items using laws dubbed the ‘Snoopers’ Charter’ in 2016 – mainly for the prevention and detection of crime or disorder.

Under the Regulation of Investigatory Powers Act (RIPA), communications can be obtained with authorisation from a designated person in a public authority.

Interception can be targeted to an individual, group or premises, while bulk interception involves a large volume of data, followed by analysis of specific items.

Data can include the location of a mobile phone, an IP address, itemised phone records, whether someone has diverted their phone, and personal user details from service providers, such as names, addresses and phone numbers.

A government transparency report into investigatory powers – presented to parliament by the Home Secretary last week – stressed the importance of public confidence in the proportionate use of powers by intelligence and law enforcement agencies.

Nationally, it reported 754,559 items acquired by authorities for the prevention and detection of crime or disorder, prevention of death or injury in an emergency or in national security interests.

Most applications are made for data related to criminal suspects or people of interest for national security, while about 15% related to identifying witnesses or locating vulnerable people.

Authorities have been required to provide details since 2015.

Authorising officer for Norfolk and Suffolk, Detective Superintendent Christopher Balmer said use of RIPA was subject to guidance, strict codes of practice and regular inspections by the Investigatory Powers Commissioner’s Office.

He added: “In today’s interconnected society, the use of communications data can be the difference between successful and failed prosecutions, as well as exonerating the innocent.

“Great care is taken to ensure RIPA is only used where there is justification for a specific investigation, and in a way that is both proportionate and compatible with human rights.

“Recent inspections of the joint communications data investigation unit have found the forces to be operating to a very high standard of compliance.”