The Torch started as a vague idea about somebody on board the TARDIS being stuck with this rather superior and annoying personality who was desperately important to the population of a distant planet, but who would not be especially popular aboard the TARDIS. I had the original idea long before I introduced Ben as a character, and it was likely to have been Donna who was burdened with the Torch piggy backing on her personality. This would have been an interesting proposition since feisty Donna would probably have fought with the superior Torch all the way.

But I decided to use Ben instead, mainly because the contrast between his basic education and the intellectual Torch was also an interesting idea. And also because I wanted to leave Ben at the end of the story with the ability to read and write confidently. Having introduced him as an illiterate, and set up Donna teaching him to read, I really wanted to move things on. Firstly, it is a bit of a nuisance having to dumb down Ben’s language and consider whether certain words would be in his vocabulary. Secondly, because I am leaning towards him and Donna as a romantic item, and it is natural that Ben would feel he isn’t her equal as long as she is his teacher. After being so irritating for so long, therefore, the Torch actually does some good by leaving Ben with that parting gift.

The story needed an element of tension, so the problem with the broken cloning tanks and the dead clones was introduced as a way of letting science, through The Doctor, the greatest scientific genius in the universe, so we think, provide the solution to the problem. It was touch and go for Ben, but of course we’re not going to kill the poor lad. Not while Donna obviously has a thing for him.

Making the new Torch body a mini-me, was an idea that came to me after looking back at the last time The Doctor cloned anyone – in the story ‘I Enjoy Being a Girl’. In that story he created a two year old baby body for Stella, who then lost all of her identity and had to start again as a baby. This time, the Torch needed to keep her personality and identity, but time was still short. So she got a reduced clone body. And why not?

Yes, sooner or later, Donna and Ben will leave The Doctor together. I still haven’t worked out what she’s going to say to her mum who thinks she’s going with The Doctor. But we shall see!