If you’ve bought one of the recent Doctor Who Blu-ray box sets, you may have discovered bonus discs containing a wealth of behind-the-scenes material, including camera scripts for some of the stories. For episodes that exist, camera scripts can be of limited interest; the only noteworthy moments are those points where the finished episodes differ from them. But by comparing camera scripts to existing episodes, you can appreciate how much information on what an episode looks like can be gleaned from its script – and this, of course, is invaluable when it comes to episodes that don’t exist.