‘Palaeo’ literally means old. Here we demonstrate current knowledge about the changing geography of Britain. For much of the period covered by this timeline Britain was a peninsula, not an island as it is today. Our predecessors would have been able to walk across our seabed to reach the current coastline. More than that, the areas we think of as seabed would have (at times) been dry plains crossed by rivers. Being topographically lower, these areas are likely to have offered more protection from the arctic conditions and this is why the offshore zone has great potential for Palaeolithic artefacts and the understanding of human origins. Four species of hominin have so far been identified as reaching our shores: