A prisoner hit a fellow inmate so hard over the head with a broom that the victim’s brain moved, a court heard.
Daniel Sanders went to Peter McDonald’s cell in an argument about noise and locked himself inside before carrying out an attack which nearly killed him.
Sanders, aged 25, has been jailed again for the attack at Channings Wood Prison in Newton Abbot.
The victim was saved by paramedics who brought him back from the brink of death when he suffered a fit as a result of a severely fractured skull.
He had to be transferred to the neurological unit at Derriford Hospital in Plymouth where he was put into an induced coma and spent three weeks in intensive care, Exeter Crown Court was told.
Sanders, of Melbourne Road, in Liskeard, admitted causing grievous bodily harm and was jailed for 32 months by Recorder Paul Derbyshire.
At the time of the attack he was serving an 18- month sentence for a burglary in St Austell and an assault in Liskeard.
The recorder told him: “This was a very nasty assault which resulted in very serious injuries.
“You were both serving prisoners and there had been friction between you.
“You went to his cell and closed the door, locking you both in.
“There was a fight and you picked up a broom and hit him with such force it not only fractured his skull but dislodged the brain.
“It was such a severe depressed fracture that it shifted the brain by a centimetre for a while.
“It is extraordinary he recovered from such a serious injury.
“It was a significant blow and had it not been for the prompt action of those at the scene and the doctors at the hospital you would be facing a much more serious charge.”
Nigel Wraith, prosecuting, said prison staff were alerted by another inmate and by the alarm from the cell and had difficulty getting inside because McDonald’s semi-conscious body was blocking the door.
“When the prison officer got into the cell he saw Sanders at the back,” Mr Wraith said.
“There was not enough room to treat Mr McDonald in the cell so he was dragged from the cell and worked on in the corridor.
“He had a fit and became convulsive and had trouble breathing as paramedics arrived and he was taken to Torbay Hospital, then to the neurological unit at Derriford.
“He was kept in a medically induced coma for three weeks but eventually made a full recovery.”
Mary McCarthy, defending, said Sanders kept a diary in which he recorded how he was becoming agitated by noise from inmates in nearby cells.
She said he had not intended to cause such serious injury and picked up the broom to swing at his legs, missing them and hitting his head by accident.