Some 15 seconds of violence resulted in a Weston-super-Mare man being jailed for nine years.
Anthony Matthews, 48, was returning home after being out with his partner when he tried to diffuse a row between two men, Bristol Crown Court heard.
But when one of the men made a comment, Matthews punched him to the ground – knocking him out – and kicked and stamped on his head.
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The court heard victim Neil Kelly suffered a life-changing bleed on the brain as a result.
Matthews, 48, of Cairo Court in Manilla Crescent, pleaded guilty to causing grievous bodily harm with intent in April 2019.
Judge Martin Picton handed him a nine year prison sentence, comprising of six years in custody and three years on extended licence.
The judge told him: “It could have been very much worse.
“You could be here for murder and facing life imprisonment.
“It was just lucky he survived.
“It was a grave injury.”
David Scutt, prosecuting, said Mr Kelly had enjoyed drinks with a pal at a home in King’s Lane, Weston-super-Mare but they went on to row in the lane.
The court heard Matthews and his partner walked by and Matthews attempted to calm the situation down before continuing on his way.
Mr Scutt said: “Something was said by Mr Kelly.
“Mr Matthews goes back, puts him on the floor, kicks him in the face and stamps on his head repeatedly, at least four times.
“Mr Kelly was left laying motionless on the floor of King’s Lane.
“At no point was Mr Kelly aggressive towards Mr Matthews.”
The court heard Mr Kelly was hospitalised for several days and was left with symptoms of positional vertigo, commonplace after suffering a brain injury.
Matthews has previous convictions for rape as well as two grievious bodily harm offences, one of which involved a bite.
Derek Perry, defending Matthews, said: “The irony is the only reason he was there was because he was trying to placate and diffuse the situation.”
Mr Perry said his client had then walked away, but something was said and he returned and committed the offence over the course of 15 seconds.
Mr Perry told the court: “It was an impulsive thing to have done.”
The court heard Matthews was in a relationship, had a forklift driving qualification and was hoping to find work.
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