Still, she managed a mesmerising strangeness. It’s also striking how much of the modern Doctor Who can be traced to those first shows – from the theme tune to enduring ideas about who the Doctor is and why he is travelling. Remarkably, many were made up on the spot by herself and William Hartnell, who played the lead. “Bill and I put together a back story because we had to. You can’t act something unless you know what is behind it. We created the fact that he had done something to annoy the other Time Lords and they decided he had to go.”