There’s a famous 1986 TV advert for the Guardian (remember when newspapers had TV adverts?) which shows you footage of a rough-looking skinhead pelting down the street and appearing to grab at the briefcase of a startled-looking city gent. Just as the viewer is digesting this scene and drawing the conclusion that suits his or her prejudices, the screen cut away to another, wider shot: the young man, as we discover, wasn’t trying to mug the older man, but was wrestling him out of the way of a pallet of bricks collapsing overhead.