In 1971, Richard Roundtree made surely the greatest entrance in cinema history. Shaft, his big-screen debut, begins with Roundtree emerging from the subway and striding confidently on to New York’s 42nd street on a wintry morning. Neatly groomed afro, moustache and sideburns, smart suit, polo neck and long, tailored leather coat. The hi-hats and wah-wah guitar of Isaac Hayes’ funky theme tune get going. Long-distance cameras track him from high above and close cameras frame him heroically from below. He struts through the bustling streets as if he owns the place, surveying the scene, jaywalking and stopping the traffic, flipping the bird at yellow cabs, stopping to engage with local characters. It’s like Roundtree arrived fully formed.