with glacial ice, and the sea level was about 120 m lower. The climate later became warmer, and around 12,000 BCE, Great Britain, as well as much of the North Sea and the English Channel, was an expanse of low-lying tundra.

Evidence, including the contours of the present seabed, indicates that after the first main Ice Age the watershed between the North Sea and the English Channel extended east from East Anglia, then southeast