A prison officer and two other people were arrested today in connection with the police probe into corrupt payments to officials by journalists.
Two men aged 46 and 37 and a woman aged 50 were held this morning at addresses in south-east London, Surrey and Kent.
They are being questioned at separate south London police stations, Scotland Yard said.
The Metropolitan Police said the 46-year-old prison officer was arrested at his south east London home on suspicion of corruption, conspiracy to commit bribery and conspiracy to cause misconduct in a public office.
Officers arrested the 50-year-old woman at a non-residential address in Kent and the 37-year-old man at his home in Morden, Surrey, on suspicion of the same offences.
So far a total of 37 people have been arrested in connection with Operation Elveden, the investigation into suspected corrupt payments to public officials.