Three prison officers were taken to hospital with suspected broken bones after Glasgow murderer sparked a 'near riot' in jail.
Mark Moncrieff, who brags about being a member of the feared Lyons crime gang and a second man, James Smith, are understood to have been involved in a stand-off at Shotts prison.
The 35-year-old is believed to have been under the influence of drink and drugs at the time, the Sunday Mail reports.
Tensions are believed to have been running high at the 553-capacity prison ahead of the incident.
The drama unfolded last Thursday, sources told the Mail.
Once said: "Moncrieff thinks he's a hard man and is always bragging about his connection to the Lyons crime gang.
"He attacked a fellow prisoner seemingly out of the blue. Moncrieff was clearly off his face.
"Smith then started threatening staff and encouraging others by saying he would give £50,000 to -anyone who slashed a guard."
Moncrieff then barricaded himself into the kitchen area, armed with a blade and broom handle.
He was eventually restrained by riot-trained staff before being moved to the Separation Integration Unit.
While being moved to the unit - dubbed "the Digger" - he injured a further three guards.
The incident saw five staff injured in total with three taken to hospital for further tests.
Injuries included a suspected broken wrist, finger and rib.
Scots Tory community safety spokesman Russell Findlay MSP said: "This violent outbreak was terrifying and it's lucky that no one was more seriously injured or even killed."
An SPS spokesman said: "Three of our staff have been taken to hospital following an incident last Thursday."
Moncrieff murdered dad Brian Boyle in Glasgow's Dennistoun in 2018.
Smith, from Cumbernauld, was jailed in 2019 for eight years for spraying acid on three victims at a flat party over an alleged drugs debt.