It is nearly four years since Black Lives Matter had their first major protest in London. Emulating their US counterparts, the protestors held up their hands and chanted ‘Hands up, don’t shoot’, a chant popularised after the 2014 killing of Michael Brown in Ferguson, Missouri. By then it had been known for a year that before his death Brown almost certainly said no such thing and had lunged for the arresting officer’s gun before being shot.