Overview: Over the last two-and-a-half million years, Britain has experienced numerous deep freezes that left the land uninhabitable and locked under ice sheets over a mile thick. Tracing the movement of the frozen wastes, Tony visits some of the country's most scenic spots - including the Scottish Highlands and the Lake District - to explore its chilly past. Ending up in London, Tony unearths the bones of monkeys, rhinos and lions that once lived on the banks of the Thames.