Michael Portillo explores the postwar Britain of his youth on a railway journey from the Midlands to the West Country.Beginning in Derby's famous 19th-century railway works, Michael hears how the Victorian sheds now house some of the most up to date assembly lines in Britain for building electric trains. In Leicester, Michael looks back to the early 1970s, when around 10,000 Asians arrived in the city after being expelled from Uganda by the dictator Idi Amin.On the outskirts of the city, Michael discovers a factory where, shortly after the Second World War, an entrepreneurial butcher turned his hand to something completely different - with the company he founded, Walkers, now producing 11 million bags of crisps a day. And from Hinkley Station, Michael heads for Stoney Cove, where a submerged quarry proved an ideal place to train divers in the 60s and 70s.