 This glaciation took place between about 500,000 to 400,000 years ago, and was responsible for the diversion of the River Thames onto its present course.There is extensive evidence in the form of stone tools that southern England was colonised by human populations during the warm Hoxnian Stage period that followed the glaciation of the Anglian Stage.It is possible that the English Channel repeatedly opened and closed during this period, causing Britain to become an island from time to time.