I have a regular anxiety scenario: I have been transported back into the nightmare of the past and have to try and explain television or phones or zips to the finest minds of the time. Obviously I can’t do it. I gabble random words and phrases I’ve picked up from Newsround and adverts – they make no sense. I imagine my audience divided between those who think I am a charlatan or a witch and want to burn me and those who believe me, believe in the possibility of the things of which I speak and are all the more furious at my failure to possess a single useful fact. They also want to burn me.