The Met has made its 36th arrest in the Operation Elveden investigation into illegal payments to police and public officials.
A 31-year-old man, described by police as a former NHS employee, was arrested at 6am at an address in Uxbridge.
The man was arrested on suspicion of conspiracy to cause misconduct in a public office and on suspicion of corruption.
He is being questioned at a west London police station.
Police said today's arrest was the result of information provided to police by News Corp'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,'the Met said in a statement.
Figures obtained by Press Gazette earlier this month revealed that Operation Elveden has so far cost £1.5m and employed 36 officers and nine staff.