A prison officer had part of his ear bitten off by an inmate during an attack at Nottingham Prison.
Nottinghamshire Police said it was called to HMP Nottingham just before 9.30am on Wednesday to reports that an officer had been assaulted by an inmate.
The officer was taken to Queen’s Medical Centre for treatment.
The Ministry of Justice said it has passed the matter to Nottinghamshire Police for investigation.
A spokeswoman for Nottinghamshire Police said: “Police were called to HMP Nottingham at 9.28am on Wednesday (July 30, 2014).
“A prison officer had been assaulted and suffered a wound to his ear. He was taken to Nottingham’s Queen’s Medical Centre.
“An investigation is under way.”
A Prison Service spokesperson said: “Prison staff do an excellent job and their safety and security is of paramount importance. Anyone who is violent towards them – or anyone else in prison – can expect to face severe consequences.
“We have referred this incident to the police and are helping them with their inquiries. We always press for the most serious charges to be laid against anyone who is violent in prison.”