Dr Francis Pryor has spent thirty years studying the prehistory of fens. He has excavated sites as diverse as Bronze Age farms, field systems and entire Iron Age villages. From 1980 he turned his attention to pre-Roman religion and has excavated barrows, ‘henges’, and a large ceremonial centre dating to 3800 BC. In 1982, while working in a drainage dyke at Flag Fen, on the outskirts of Peterborough, he discovered the waterlogged timbers of a Bronze Age religious site. In 1987, with his wife Maisie Taylor, he set up the Fenland Archaeological Trust, which opened Flag Fen to the public. He is the author of Seahenge and Britain BC, an authoritative rethinking of pre-Roman British history, which was televised as a three-part documentary by Channel 4, as well as Britain AD and Britain in the Middle Ages: An Archaeological History of Britain.