How do the police carry out a 'hard stop'?
8 January 2014 Last updated at 16:07 GMT
Mark Duggan, whose death sparked riots in England in 2011, was lawfully killed, an inquest jury has said by a majority of 8 to 2.
The 29-year-old was killed in August 2011 in Tottenham, north London, after police stopped a taxi in which he was travelling.
Using footage from a training exercise conducted by the National Crime Agency, the BBC's Danny Shaw explains how police conduct a hard stop - which was the kind of tactic used when Mark Duggan was pulled over.