A 29-year-old prison officer has been arrested following an investigation into corruption at a women's jail.
The female officer, from Vauxhall in Liverpool, was based at HMP Styal in Cheshire, the North West Regional Organised Crime Unit (NWROCU) said.
She was arrested on Thursday on suspicion of misconduct in a public office and attempting to pervert the course of justice.
The prison officer has been taken to a local police station for questioning.
HMP Styal is a closed category prison for women and young offenders, based in the village of Styal, near Wilmslow, in Cheshire.
The arrest was part of a joint investigation between Her Majesty's Prison and Probation Service, HM Courts & Tribunals Service and the NWROCU to try to reduce corruption in the prison service.
Det Sgt John Davies from NWROCU said: "We know the vast majority of prison officers are dedicated professionals who carry out their duties with integrity but today's activity is another positive step in tackling prison corruption in the North West and we will continue our efforts to bring offenders to justice."