A march steward caused a brain injury to a stranger who he pushed to the ground when violence flared after a city centre protest.
Dean Lawrence, 42, had provided security for the Democratic Football Lads Alliance (DFLA) during their march in Sunderland in September 2018, which was met with counter protesters on the day.
Newcastle Crown Court heard in the hours after the event, some of the attendees went drinking in bars.
Prosecutor Alec Burns told the court two men walking home from the pub, through a park behind Crowtree Leisure Centre, came under attack.
One victim, who had been at the counter-protest and had been involved in “banter” with the DFLA during the event, was punched to the ground and beaten by an unknown attacker.
His friend, who had not been at the march, was pushed to the ground by married dad-of-two Lawrence and left with four areas of intracranial bruising with bleeding on the brain.
Mr Burns told the court: “He pushed the complainant and knocked him to the ground. He had no time to react and wasn’t able to soften the blow and hit the ground with his head, which knocked him unconscious.”
The court heard Lawrence walked away and left his victim on the ground.
His victim spent three days in hospital, with an injury prosecutors said could potentially be fatal, and was unable to drive for seven months after the attack.
He said in an impact statement he was left with painful headaches and when out alone he is always “wondering if i’m going to be attacked again”.
He added: “I don’t think I will ever get over the psychological effect this had on me.
“I am trying to take each day as it comes in the hope that as time goes by it will become easier to deal with.”
Lawrence, of Aintree Close, Catshill, Bromsgrove, West Midlands, admitted causing grievous bodily harm.
Judge Julie Clemitson sentenced him to 20 months behind bars, suspended for two years, with a £2,500 compensation order.
The judge told him: “You left, you walked away, you left him there without checking to see if he was alright.”
Judge Clemitson said Lawrence has since “distanced himself” from the DFLA organisation, has positive references, has never been in trouble before and is remorseful for the attack, which faced delay in being concluded in court.
The judge added that the current public health crisis had influence over her decision to suspend the jail term.
Steven Reed, defending, said Lawrence struggled to accept what he had done in the aftermath of the violence and was “scared”.
Mr Reed said Lawrence had been a steward at the march and had gone to the pub afterwards.
He adde: “In relation to the confrontation in the park, he went there with the intention of preventing a confrontation, not being involved in a confrontation.”
Mr Reed said Lawrence has raised money for charities supporting homelessness and autism and got himself “caught up through naivety”.