An inmate who attacked prison officers and another prisoner because "angels told him to kill" has been given three life sentences.
Aklakur Rahman, 33, carried out the attacks at prisons in Norfolk, Lincoln and Wakefield.
Rahman, who is originally from Ipswich, used makeshift weapons, including razor blades and a piece of masonry.
He was sentenced at Birmingham Crown Court on Friday and must serve a minimum of 13 years.
Rahman was convicted in July of attempting to murder Derek Walker and fellow inmate David Sutton at HMP Wayland, near Thetford, in July 2017.
The men suffered serious head and neck injuries after being attacked with a weapon made from a razor blade.
One needed 28 stitches while the other suffered extensive nerve damage, police said.
'Extremely serious injuries'
Rahman was also found guilty of attempting to murder Sean Humphries with a sharpened piece of masonry, following an attack at Lincoln Prison days later.
Rahman was given an additional five-year sentence for attacking Daniel Preston with a screw at HMP Wakefield jail, in August 2017. The sentences will run concurrently.
During his trial at Lincoln Crown Court, Rahman did not deny the attacks but said he was clinically insane at the time.
He said angels had told him to kill people and told him he would be punished if he did not follow their instructions.
Speaking after sentencing Det Insp Kevin Brown, of the East Midlands Special Operations Unit, said: "Two of his four victims received extremely serious injuries to their heads or necks, ones that they are still feeling the effects of to this day."
"All four continue to suffer psychologically as a result."