The earliest known fossil remains of a polar bear come from Kew. So, when polar bears swam in the Thames, did Britain really look like present-day Greenland? What was the Ice Age? Was it so long ago? The tusks of the most famous of all extinct Ice Age mammals, the woolly mammoth, were found in Cae-Gwyn cave in North Wales. According to radio-active dating they'd lain there for 18,000 years, but it's a mere 12,000 years, say geologists, since Britain had glaciers.
In tonight's programme we see by means of an Icelandic glacier the processes that shaped the British landscape. We also find out how scientists are reconstructing the extreme climatic changes of the last 100,000 years-from the evidence of the rocks, fossils, botany, even beetles, and we ask: why did it happen? Will it happen again?