Michael Portillo takes to the tracks with a copy of George Bradshaw's Victorian Railway Guidebook. Portillo travels the length and breadth of the country to see how the railways changed us, and what of Bradshaw's Britain remains, as his journey follows the route of the Irish mail from Ledbury to Holyhead. Michael visits the world's first Iron bridge at Coalbrookdale, explores the historic Chirk castle and has a go at making traditional Cheshire cheese.