A murderer who punched a prison officer claimed his drink had been spiked with a legal high.
Robert Morrison, 32, became unwell behind bars at HMP Shotts and needed medical treatment.
But while being assessed he became irate and punched guard Stephen Hardie in the face.
The force of the blow left the officer with blood pouring from his mouth and nose.
During a prison interview over the incident, the killer said: "I cracked the officer once, but he cracked me three times."
Morrison, jailed for the brutal slaying of 19-year-old Matthew Drummond, appeared at Hamilton Sheriff Court today and admitted the assault.
His lawyer claimed he had been spiked with a legal high which had led to him becoming unwell in August 2019.
Sheriff Linda Nicolson handed Morrison a sentence of 245 days for the attack but told him it would run alongside his current minimum 16-year sentence for murder.
The court was told his earliest date of release is in 2027.
Depute fiscal Rebecca Clark said: "The complainer in this case, a prison officer within Shotts prison, entered the accused's cell to accompany a nurse to carry out a health check.
"During this, the accused took issue with an aspect of it and became angry.
"He stood up from the bed and punched the prison officer once on the face and the nurse immediately pressed the cell alarm for assistance.
"Help arrived and the accused was restrained.
"The complainer Hardie was noted to have blood coming from his nose and mouth."
Sandy Morrison, defending, said: "He is serving a life term of imprisonment and the consequences of this will be the date for consideration of release will almost certainly be pushed back.
"His drink had been spiked with a legal high and he was receiving medical treatment and according to him the prison officer became aggressive with him telling him to stand up when he was unable to do so.
"He then did get up, lost his cool and struck the officer.
"As a result he lost all prison privileges for 14 days but he tells me there are no issues between him and the officer involved."
Morrison was jailed after stabbing friend Drummond four times at a house in Hamilton in January 2011.
A court heard his victim had been knifed in the stomach, neck, shoulder and head with the knife wound to Drummond's neck seven inches deep.
Jailing him at the High Court in Glasgow, judge Lord Bracadale said: "On the night of the murder, after some niggling between you and Mr Drummond, you took a knife into the street and then returned to the house and stabbed Mr Drummond a number of times.
"The consequences of that have been devastating for the family of Mr Drummond who have been left bereft."
