Heavy horses played a pivotal role in the development of western economies, toiling in mines and quarries, at mills, factories and docks, alongside canals and railway lines, in fields and pasture. But with the invention of the tractor and motor lorry their numbers plummeted, with some breeds close to extinction in the 1950s. Today, after a revival of interest, Shires, Clydesdaies, Suffolks and British Percherons attract special attention whenever...