An inmate is in a life threatening condition after he was stabbed in Chelmsford Prison.
Essex Police officers attended the incident at the prison in Springfield Road at around 9.15am on Monday.
A spokesman for Essex Police said: "We were called to reports of a stabbing inside Chelmsford Prison in Springfield Road, Chelmsford, at around 9.15am on Monday.
"Patrick Chandler, 45, of Chelmsford Prison, was arrested and has since been charged with attempted murder."
Police confirmed the victim's injuries are no longer life threatening, however, they are life changing.
Patrick Chandler was jailed for a serious offence in Manningtree last year.