A prison officer is "lucky to be alive" after having his throat cut by an inmate.
The man, said to have been a new to the job, was taken to hospital after the attack on Sunday morning at HMP Nottingham, near Birmingham.
Prison Officers' Association national chairman Mark Fairhurst said the officer received 17 stitches after being attacked with a razor in an "unprovoked attack".
"Apparently as soon as his door was unlocked this morning, he attacked the first officer he saw with a razor blade," Mr Fairhurst said.
"He has cut his neck. The officer has gone to hospital and received 17 stitches.
"At the hospital, staff said he's lucky to be alive as it was very close to the main artery on his neck."
He also said that the officer was a new member of staff still on his probationary period.
The male officer has since been released from hospital.
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A Prison Service spokeswoman said: "A prison officer received hospital treatment after an incident at HMP Nottingham this morning.
"We do not tolerate violence against our hardworking officers which is why we introduced the Assaults on Emergency Workers Act, which ensures perpetrators receive the maximum possible sentence."
An inspection report published last year found levels of violence at the prison were "very high", with 103 assaults on staff in the previous six months.
Over the same period, there had been 198 incidents where prisoners had climbed onto safety netting between landings.
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"This level of disorder contributed to a tense atmosphere at the prison," HM Inspectorate of Prisons said, adding that many violent incidents, including serious ones, were not investigated at all.
The prison needed to do "much more" to tackle the problem of drugs which was "inextricably linked" to violence, chief inspector of prisons Peter Clarke Clarke said in his report.
HMP Nottingham is a category B male prison which expanded in 2010 to hold 1,060 prisoners.
