A 69-year-old hunt supporter inflicted GBH on a protester by breaking her arm with his walking stick, a court heard.
John Hawkins lashed Lynn Phillips with the stick twice, a day after the Government announced a ban on fox-hunting, it was alleged.
Ms Phillips said she was left screaming in pain by the attack.
She told the court: "I thought I was going to die. I was hysterical."
Hawkins denies causing grievous bodily harm at the trial at Brighton Crown Court.
The jury heard violence flared at the end of a meeting of the Crawley and Horsham Hunt on January 29, 2005.
Hawkins, of Singers Farm, Henfield Road, Cowfold, is accused of attacking Ms Phillips as groups of pro and anti-hunt supporters gathered on Spear Hill at Shipley, near Horsham, to pack up and wait for vehicles to take supporters home.
The hunt supporter is alleged to have hit her twice without warning or provocation.
Giving evidence from behind a screen, Ms Phillips, a veteran antihunt protester, said at the time of the alleged attack feelings were running high as on the previous day the Government had announced fox hunting was to be banned.
She said: "Obviously they were not happy the vote had gone against them. There was a lot of verbal abuse. There seemed to be so much anger on their part."
Ms Phillips described to the jury how anti-hunt protesters would try to stop the hunt catching foxes by making a noise.
She said: "They try to outsmart us and find foxes anyway and we try to outsmart them and stop them catching foxes."
Ms Phillips said at about 4pm she was waiting on Spear Hill for a lift with about 20 other protesters but there were also many huntsmen and their followers around.
She said: "It was very tense at that point because the hunt had not caught much that day so we were feeling quite good and they were feeling quite disappointed."
Ms Phillips said she had become concerned about a hound which she believed was injured and she was standing in the road looking for the dog when she became aware of a man brandishing his walking stick at her.
She said: "I was confronted by this man with a stick above his head swinging it backwards and forwards at me. He was just staring at me. It was just horrendous. He was just so frightening to me because he looked like he hated me." Suddenly, she said, she heard a shout as a huntsman wearing a red jacket decided to canter up the middle of the crowded road.
She feared she might be run down by the horse or whipped by the rider and she turned round and moved to safety.
But, she said, at that moment she felt a painful blow on her head. She turned back and saw the man with the stick on the ground with two women helping him up and she realised he must have hit her before falling over.
She said once he was back on his feet he attacked her again.
"He had the stick right above his head. I put my arm up to try to protect my head. He hit me. I just doubled over. I was in so much pain. I thought I was going to die."
She said she became aware of anti-hunt protesters moving forward en masse to help her. But when she was taken to a van to be driven away, a hunt supporter stopped the vehicle and took the ignition key which meant it was a long time before she got home.
Two days later she went to hospital where an X-ray showed her arm was broken.
Alastair Smith, prosecuting, told the jury: "This is not about fox hunting. It is a trial about an assault." The trial continues.
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