Swanscombe in the Anglian Ice Age 450,000 years ago, looking north across the Thames [Photo Martin Bates]
During the last million years, there have been several separate Ice Ages, each lasting tens of thousands of years. Most of Britain was covered by ice sheets.
At the cold peak of ice ages, ice-sheets hundreds of metres thick would have covered most of Britain, reaching on occasion as far south as London. Rivers would have frozen solid, and the country must have been uninhabitable at these times.
In between ice ages were periods of climatic warmth - Interglacials - when the climate was as warm as, or warmer than, the present day.
Mollusc species that now inhabit the Nile were abundant in British rivers, and tropical fauna such as lion, hippopotamus, monkey and forest elephant were common in Britain.
For the majority of this time, however, the climate would have been somewhere between these extremes.
Sea-level would have been up to 100m less than the present day, and tracts of land in the English Channel and North Sea would have been exposed and available for occupation.