Two prison officers from Dorset have spoken of their fear of being attacked by inmates every time they go to work.
Tony Walker and Andy Dubber, from HMYOI Portland, said they had been assaulted and verbally abused by inmates at work.
Mr Dubber said he was once "knocked out" and Mr Walker described the prison service as being "at breaking point".
HM Prison Service said it was "committed to making prisons places of safety and reform" and there were no staff shortages at HMYOI Portland.
Mr Dubber and Mr Walker also raised concerns about overcrowding, understaffing, violence among prisoners, as well as self-harm and the availability of drugs, including the former legal high called Spice.
Mr Dubber, who has worked at the prison for more than 20 years, said he begins every shift thinking: "How am I going to get through this without being assaulted?"
Mr Walker agreed officers were "completely demoralised".
"They have to come into work and expect to be assaulted," he said.
Mr Dubber said: "I was knocked out about a year ago by a prisoner coming out of a Spice attack - head butted me from nowhere, knocked me clean out."
He described the side affects of Spice as "horrendous".
"[Prisoners] can turn very violent, they can act like drunks, they can have convulsions," he said.
Mr Walker, who has been a prison officer for 24 years, said a colleague was once "potted" by an inmate - where they mixed excrement and urine in a pot and threw it over a staff member.
"I've had 10 stitches after a brush was put over the back of my head," he said.
An inspection at HMYOI Portland in 2014 found "greater attention" needed to be paid to investigations into self-inflicted deaths and raised concerns over substance misuse.
A previous report in 2012 found there had been a rise in violence and "limited progress" in tackling self-harm.
A Prison Service spokeswoman said: "We have taken immediate action to stabilise the estate by tackling the drugs, drones and phones that undermine security.
"We are also investing £100m annually to boost the frontline by 2,500 officers."