With Bertrand Tavernier's futuristic 1980 drama, Death Watch, coming to Blu-ray and DVD on 5 November, David Compton, author of source novel 'The Continuous Katherine Mortenhoe', recalls the writing of the book and his time on the Glasgow set. Usually, when people ask writers where they get their ideas from, they receive vague, dusty answers. In the case of this book, though, my answer need be neither vague nor dusty. I remember the manner and the moment exactly.