Just back from seeing this at
Fact in Liverpool. Very powerful stuff, a potted history of some of the nastier parts of the post war period. Interviews with McCullin and his editor at the Sunday Times are intercut with film and stills of the conflicts he covered. Some of the footage is utterly horrific, executions and piles of bodies. Good pictures as well of people relaxing and playing in the UK, as well as pictures of dereliction and homelessness in London.
Well worth seeing if it's on near you.