In the UK, the availability of cheap GPS devices, and a mistaken belief that it was permitted under the Regulation of Investigatory Powers Act, led to covert tracking being used by public authorities, including local councils "without properly considering the application of the legislation, " according to watchdog the Surveillance Commissioners.

BBC: How much privacy can smartphone owners expect?

The watchdog's findings said Durham Police failed to properly scrutinise Atherton's 2006 application for a shotgun certificate and an application for a firearms licence two years later in 2008.

BBC: Durham PCC Ron Hogg calls for gun licence changes