Entries in the British Touring Car Championship tend to look like the cars we drive ourselves, though they’re very different beneath the bonnet. Jeremy Clarkson puts top drivers to the test in the production-line versions of their racing machines. And Tony Mason reports on 45 Rolls-Royce Silver Ghosts, re-creating an event last held before the First World War. Can the “best car in the world” still tackle 1,700 miles of Europe’s toughest alpine roads at more than 80 years of age?