The man, aged 31, was detained at his home in west London on Thursday morning by Scotland Yard detectives running Operation Elveden.
He was being interviewed at a police station on suspicion of conspiracy to cause misconduct in a public office, and corruption.
The man is thought to be source for the Sun or News of the World newspapers which ran a series of stories on convicts held in Broadmoor, Berkshire, including Peter Sutcliffe, the Yorkshire Ripper, and Robert Napper who killed Rachel Nickell.
Operation Elveden is looking into allegations of inappropriate payments to public officials and so far 36 arrests have been made.
The investigation is being supervised by the Independent Police Complaints Commission (IPCC).
It is linked to Operation Weeting, the investigation into the hacking of mobile phone voice messages.
A spokesman for the Metropolitan Police said: "Today's arrest is the result of information provided to police by News Corporation's Management Standards Committee.
"It relates to suspected payments to a public official and is not about seeking journalists to reveal confidential sources in relation to information that has been obtained legitimately."
Officers investigating allegations of inappropriate payments to police and public officials arrested the man, described as a "former NHS employee" in Uxbridge at about 6am, according to the spokesman.
He was held on suspicion of conspiracy to cause misconduct in a public office contrary to Common Law and on suspicion of corruption contrary to the Prevention of Corruption Act 1906.