by Tracy McVeigh and Vanessa Thorpe, The Guardian, UK - Among the recent flurry of mainstream films set in Africa there has been an inescapable common thread. Blood Diamond, The Last King of Scotland, Shooting Dogs and The Constant Gardener: all well-received, all acclaimed, and all with white protagonists heroically engaging with a dangerous and savage continent.That pattern may be about to change. Later this month five young, unknown Africans will walk up the red carpet in London's Leicester Square to the British premiere of a film which discards the usual Hollywood stereotypes.