A prison officer and two other people have been arrested by police investigating corrupt payments to public officials by journalists, Scotland Yard has said.
The Operation Elveden arrests were carried out on Wednesday morning, the Metropolitan Police added.
The prison officer, 46, a man aged 37, and a woman aged 50 were arrested in south-east London, Surrey and Kent.
They are being questioned at separate London police stations, police said.
The arrests, which happened between 06:00 BST and 08:00 BST, bring the total during the inquiry to 37, police said.
The prison officer was arrested at his home address in south-east London on suspicion of corruption, on suspicion of conspiracy to commit bribery, and on suspicion of conspiracy to cause misconduct in a public office.
The woman was arrested at a non-residential location in Kent on suspicion of the same three charges, while the other man was arrested at his home address in Morden, south London, also on suspicion of the same three charges.
Operation Elveden is being run in conjunction with Operation Weeting, the police inquiry into the hacking of mobile phone voicemails.
