Police officers were pelted with eggs and milkshakes by teenagers who were causing chaos in Manchester City Centre.
Hundreds of children in uniform were seen running riot around Piccadilly Gardens yesterday, after finishing school for the summer.
As the youths ran amok shops were forced to lock their doors and tram services were brought to a crawl.
One eyewitness said the group then headed up Market Street, where they were joined by teenagers from other schools.
This follows a similar scene when around 100 pupils attacked police officers, in January last year.
A tactical aid unit was drafted in to help control the mayhem, which reportedly started after a group of teens was asked to leave the food court at the Arndale shopping centre at about 2.30pm.
Shortly after 5pm, a dispersal order was put in place and one person was reportedly arrested after being chased through Piccadilly Gardens by officers.
Despite warnings from police to disperse, the crowds spent the best part of two hours shouting and screaming, witnesses said.
Officers warned those gathered that they may be arrested if they refused to move when asked.
Video footage shows throngs of youths moving past Primark in the direction of Piccadilly Gardens.
Manchester councillor Pat Karney slammed the ‘disgraceful behaviour’ of those involved and warned that action would be taken.
‘It is just disgraceful,’ he said. ‘Hundreds of youngsters – we know it is the last day of school, and we have all been there and loved it – but you don’t come down to the centre of Manchester to stop the trams, throw eggs at the cops, and cause mayhem in the area and think that’s fun.
‘We will have pictures of these kids – we have a lot of cameras in Piccadilly and the tram stops – and we will be contacting the schools they come from. This will not be allowed in the city centre. We are not putting up with this nonsense.’