The gang war being waged on Britain's streets
22 November 2012 Last updated at 21:54 GMT
A man accused of fatally stabbing a teenager in Oxford Street on Boxing Day last year has been found not guilty of murder and manslaughter.
The Old Bailey heard that Jermaine Joseph, who's 23, was acting in self defence after being chased into a shop by 18-year-old Seydou Diarrassouba.
The case highlights the gang violence that poses a real threat on Britain's street, as the BBC's Home Affairs Correspondent Tom Symonds reports.
CCTV footage courtesy of Crimestoppers, BBC One