A shop worker was kicked and stamped on by a vicious girl gang when she tried to stop their attack on a homeless man at South Shields Metro station.
The youths had targeted their first, vulnerable victim when they saw him drinking from a bottle of cider and decided theywanted it.
In the "bullying" violence that followed, one of the youths tried to push the man down the station stairs before he was beaten and kicked.
When a nearby shopworker stepped in to stop the violence, the feral females turned on her.
The 55-year-old was knocked to the ground where she was also kicked and stamped on.
She told police after the shocking attack last April: "I was trying to defend a member of the public and these youths have turned on me.
"I cannot believe I was powerless to stop this happening to me.
"I felt defenceless."
The girls involved in the sickening attacks were all dealt with by the youth court and given various non-custodial sentences.
At Newcastle Crown Court David Walby, of Ewe Hill Terrace, Fence Houses, admitted his part in the affray.
The court heard the autistic 22-year-old was easily led and had not instigated the violence that day.
Judge Tim Gittins sentenced him to eight months imprisonment, suspended for two years, with programme requirements and a three month night time curfew.
The judge told him: "This was a prolonged and sustained incident that lasted about ten minutes.
"Fortunately, remarkably, no serious injuries seem to have followed but undoubtedly they were left in pain, discomfort and no doubt terrified about what was going to happen to them and fear of it happening again.
"This was attacks on two people, that included kicks and stamps, on a vulnerable complainant and an innocent woman who sought to intervene to help him."
Judge Gittins said despite Walby being older and bigger than his co-accused, it was they who started the trouble and he joined in to try and please them.
The judge said input from the probation service would be better to prevent future offending than a prison sentence in Walby's case.
Paul Currer, defending, said Walby, who has since been the victim of a violent attack himself, had been drinking alcohol that day and was willing to work with officials who could help him.