Green’s Dictionary of Slang

pertaining to a hooligan.

1991		D. Widgery Some Lives! 105: Baby-faced heroin addict from Bootle. Scally clothing, arm full of tracks.
2000		J.J. Connolly Layer Cake 136: Duncan ain’t got the scally accent that Trevor and shanks have got.
2000		N. Griffiths Grits 288: Fuck knows wharrit [i.e. an anecdote] means [...] it’s just about a little scally kid anner caged wolf.