Going on their behaviour, their treatment of the girl, the comments made by her mother about the area and the fact they need to be in a 20-strong gang to act this way, I'm going to take a guess and say they are adherents of the Religion of Peace.
From The Rochdale Observer:
I've taken a chance with this one, as Greater Manchester Police and the local newspapers in northern England generally are not afraid to describe suspects - however the spitting and the name calling, along with the sheer number involved, sounds like classic harassment of Western women by 'youths' to me.
A YOUNG woman was left battered and bruised after being set upon by a gang of about 20 youths,
Emily Bridge, aged 19, was approached by the gang who tried to start a conversation and distract her before making a grab for her bag.
At first she attempted to put up a fight and managed to snatch her bag back, but with the teenagers surrounding her she couldn’t escape.
The gang stole her bag and purse worth £140 before half a dozen of the youths began hitting her round the head and body.
The attack, which took place in Richard Street at about 7pm on 14 August, lasted for only a few minutes, but Emily, of Rooley Moor Road, was left with cuts and bruises before being spat on as the gang walked away.
She said: "They just came up and started talking – I was scared. They started calling me names so I just walked off and then they went for my handbag. At first I grabbed my bag back off them, but then all of them started jumping in. I tried fighting back. I had bruises on my knees and bumps all over my head, grazes on my elbows and a sore back after the attack. I can't remember it that well, there were loads of them and I just wanted to get away."
Her mother, Jeannette Bridge, added: "They do it all the time to girls up there – it's happened to me. I had a cut on my head where I'd been hit with a vodka bottle. It happens every other week by the train station, Drake Street and Fishwick Street – they're just targeting girls."
Police have taken Emily's clothes to try and find forensic evidence to identify the culprits, who are all thought to be aged between 14 and 17.
A GMP spokesman said: "Police are investigating a robbery in Rochdale. The 19-year-old victim was approached on Richard Street by a large group of men and one of the gang tried to snatch her handbag. The strap broke and the bag was stolen while other members of the gang struck the victim in the face and body before running off. The gang responsible are thought to be in their teens. Inquiries are ongoing."