Ice will have covered the isles of Pretani or Pretania, known today as the British Isles, but as it became warmer the ice sheet gradually melted and retreated northwards exposing land connecting mainland Europe with the largest island now known as Britain.
This exposed area of land was a wide undulating plain containing river systems, channels, lakes, mudflats, marshes and beaches. It was a rich hunting ground for animals and fish and a land bridge into Britain. As it became even warmer the ice sheet gradually melted further with this melt water starting to cover the land bridge between mainland Europe and Britain. The remaining land became completely immersed following a catastrophic event. A tsunami was triggered when a landslide occurred under water at the edge of what is now known as Norway’s continental shelf. It resulted in a long high sea wave in the North Atlantic Ocean which submerged the remaining area of land known as Doggerland beneath the North Sea. Britain was now separated from the European mainland.