Kidulthood Opening Sequence

I watched the opening sequence of the British urban drama called 'Kidulthood' (Directed by Menhaj Huda and written by Noel Clarke, 2006). The characters in the film generally behave in a violent, lawless manner and are reckless and antisocial, with petty theft, serious violence, and drug taking endemic in the culture portrayed. 
The opening sequence opens in a school playground with all sorts of children playing and talking and having fun in their own way.