Inspired by the friendship that developed between Nelson Mandela and prison guard James Gregory during the former’s 18 years on Robben Island, the story behind Bille August’s latest is almost too good to be true. Indeed it might not be true at all, Nelson’s official biographer having accused his gaoler of making the whole thing up. If you can handle a bit of dramatic licence, though, Goodbye Bafana should keep you locked in for most of its generous running time. Its central relationship brings back unhappy memories of Cry Freedom – another portrait of Apartheid viewed from a white perspective – but it narrowly avoids being a sanctimonious plod thanks to its leads. As Gregory, Joseph Fiennes makes a convincing transformation from racist bully to contrite acolyte, while Dennis Haysbert – no stranger to benevolent nobility after four seasons on 24 – does what he can to make Mandela a man as well as a saint.