An inmate has been stabbed in the neck with a makeshift knife at HMP Swaleside on the Isle of Sheppey, Sky News understands.
The prisoner, who is in his 30s and has not been named, reportedly left the category B prison in Kent in an ambulance.
He is said to have been attacked with a handmade knife known as a “shank”.
The stabbing at the category B prison reportedly place at around 7:30pm.
It comes after another inmate was said to have been stabbed multiple times in the head at the prison last Friday.
The man in his 20s is reportedly still in intensive care.
A weapon amnesty was held in the prison urging inmates to hand in their knives in March.
The prison and the Ministry of Justice have been contacted for comment.