A former Metropolitan Police officer was arrested by detectives from the police watchdog on Tuesday over allegations he passed unauthorised information to a journalist.
The 52-year-old was held at his home in Berkshire on suspicion of misconduct in a public office and Data Protection Act offences, the Independent Police Complaints Commission (IPCC) said.
The IPCC said the arrest resulted from information obtained by detectives from the Met Police's Operation Elveden team which is looking into claims journalists paid police in return for information.
That inquiry is running alongside the investigation into phone-hacking centred on the defunct News of the World newspaper.
(Reporting by Michael Holden)