Fleam Dyke

Fleam Dyke is a long earthwork running between Fulbourn and Balsham in Cambridgeshire. It stretches for three miles across a chalk ridge, with a ditch on its southwest side and a bank seven metres high. Near Fulbourn the dyke meets marshy fenland, while near Balsham it passes close to Mutlow Hill, topped by a Bronze Age burial mound. The earthwork was built in several phases, first between AD 330 and 510, and last between AD 450 and 620. A footpath follows the crest of the bank as part of the Harcamlow Way long-distance route. The dyke was likely constructed by early Anglo-Saxon settlers as a defence against Romano-British attempts to regain territory. Later it marked the boundary between Anglo-Saxon administrative divisions called hundreds. Excavations found a fourth-century Roman coin beneath the bank and Anglo-Saxon weapons and burials nearby. The dyke’s ditch faces southwest, suggesting it was built to resist attacks from that direction. At Mutlow Hill the earthwork runs beside an ancient barrow containing eight urns of cremated remains. Visitors can walk the footpath along the dyke’s crest and see the steep banks covered in chalk grassland. The site supports rare plants including the only Cambridgeshire population of common juniper. A Bronze Age barrow stands beside the dyke at Mutlow Hill, and the whole length is protected as a Scheduled Monument. The area is also a Site of Special Scientific Interest, recognised for its wildlife value since 1912. The earthwork forms part of a network of similar defences across the region.