A police officer has been stabbed in the chest at HMP Frankland, Durham Police said.
The officer, who is from Greater Manchester Police, was injured just after 11am on Tuesday.
He was taken to hospital and is said to be conscious and talking.
“A police officer, who was visiting the facility from an outside force, suffered a stab wound to the chest during the incident.
“The injured officer has been taken to hospital by ambulance, where he is described as being ‘conscious and talking’.”
A local resident said they saw the air ambulance land nearby.
Justice Secretary Shabana Mahmood said on X, formerly Twitter: “Deeply concerning news from HMP Frankland today, where a police officer has been stabbed, though is conscious and talking in hospital.
“I am being kept up-to-date with all developments. And my thoughts are with that brave officer.”
HMP Frankland is a category A men’s prison, the highest level of security.
Inmates being held at the jail include Damien Bendall, who is serving a whole life term for murdering his partner Terri Harris, 35, her daughter Lacey Bennett, 11, her son John Paul Bennett, 13, and Lacey’s friend Connie Gent, also 11, in Killamarsh, Derbyshire, in 2021.
The Sun reported in May that he had attacked another inmate at the prison with a claw hammer.
Other prisoners being held at the jail are thought to include Wayne Couzens, the-then serving police officer who kidnapped, raped and murdered Sarah Everard, and Levi Bellfield, who killed Milly Dowler, Marsha McDonnell and Amelie Delagrange, and tried to kill Kate Sheedy.
Double murderer and necrophiliac David Fuller appeared via videolink from the jail for his trial for sexually abusing bodies in 2022, while Soham murderer Ian Huntley is also said to be held there.
Liberian war criminal Charles Taylor, who is serving a 50-year sentence, is another notorious Frankland resident.