Actor Derek Jacobi grew up in Walthamstow, where his parents ran a market stall. But a clue in his mother's family tree hints at a more colourful past - his great-grandmother's name was Salome Laplain. Armed with this tantalising detail, Derek discovers that, far from being from humble roots as he had thought, he is in fact descended from a wealthy French Huguenot fleeing religious persecution in France - who had connections to Protestant royalty on this side of the channel.