I began this book waiting for a diesel train to Derby, under the windy, boxy, flat-roofed bit which one of Sir Norman Foster’s team added to the back end of St Pancras station. At around 7 p.m. on a weekday only a dozen or so people were travelling. In the arcade below — built by the proud Midland Railway, as Christian Wolmar reminds us, to the dimensions of the Burton beer barrels the space was designed to store — shops are being boarded up.