As we eat our salads – I have ordered beetroot salad with goats’ cheese, chives and shallots – I take the opportunity of having this master craftsman in front of me to ask about writing. He commences by defining where others go wrong. “Anyone can write five people trapped in a snowstorm. The question is how you get them into the snowstorm. It’s hard to write a good play because it’s hard to structure a plot. If you can think of it off the top of your head, so can the audience. To think of a plot that is, as Aristotle says, surprising and yet inevitable, is a lot, lot, lot of work.”