Book excerpt: In his new book, well-known London cabbie Alf Townsend tells us the complete story of the black cab, from its origins at the time of Oliver Cromwell to the brand new taxis which now grace the capital's streets. This light-hearted romp through the world of 'the knowledge', the vehicles, the streets of London and the cabbies themselves, is full of juicy snippets and fascinating quotes and, with a multitude of great pictures too, is a must-have for anyone who loves this world-famous London icon.