A police force used the Regulation of Investigatory Powers Act to bug a journalist's car – but has denied using it to obtain a news agency's phone records.

Thames Valley Police bugged part-time Milton Keynes Citizen journalist Sally Murrer's car in December 2006 to find the source of leaked stories about the force.

Murrer was charged with conspiring to commit misconduct in a public office after a police officer allegedly leaked her confidential information, but evidence against her was ruled inadmissible after a five-day legal battle at Kingston Crown Court.