Happisburgh on Thames
During the earliest periods of human occupation, the geography of Britain differed considerably from that of today. Britain was not an island but a peninsula of the north-west European continent.
There was no English Channel, but a precursor of the river Thames flowed, far to the north of its present valley, reaching the North Sea at Happisburgh. This land bridge was the point of entry into Britain for migrating animals, including humans. The following maps show how the geography of Britain evolved during a period of about half a million years, culminating with the most extensive period of glaciation, known as the Anglian, about 450,000 years ago.