Two men have denied trying to murder a prison officer at a maximum security jail in Cambridgeshire.
The officer suffered stab wounds to his head, chest and face as cells were unlocked at HMP Whitemoor, near March, on January 9.
Brusthom Ziamani, 24, and Baz Hockton, 26, each pleaded not guilty to attempted murder but admitted a charge of wounding with intent when they appeared on video-link at the Old Bailey.
Ziamani also pleaded guilty to charges of assault causing actual bodily harm and assault by beating.
A two-week trial has been set to begin at the Old Bailey on September 21.