Gideon and Iris came from a discussion on my forum about the upcoming Doctor Who Christmas specials of 2009. One of the speculations about the storylines was that The Doctor and Wilf Mott would consider the nature of age and death. I thought that The Doctor, looking young, considering age and death was an interesting notion, and decided I would get in a story before Christmas, exploring that theme my own way. I actually did a Torchwood story in which immortal Jack faced old age and death through a man he had come to know, and that was one way of doing it. But I also had the idea of The Doctor meeting a Human who had lived a life he would recognise.

Gideon is named after a character called Jason Gideon in a TV series called Criminal Minds. I have never seen the series, ever, but I have a friend who loves it and talks about it all the time. The name stuck in my mind. Iris, is the name of a woman I got to know as a friend in the same week I was writing this story, and I decided her name would do for Gideon’s daughter. She doesn’t know about it yet! She’s still working through my stories.

I’m not sure where the idea of the TARDIS bumping into another time machine in the vortex came from. Possibly the collision with the Titanic in Voyage of the Damned. Anyway, the important thing was what the other time machine should look like. I considered several options before settling on a 1970s Volkswagon campervan because they are so iconic and redolent of that period.

My first idea of how Gideon came by the information about how to build a time machine was some kind of interaction with The Doctor either when he was in his first incarnation in London, or later when he was exiled on Earth in his third life. But then I remembered The Tenth Doctor’s adventures in 1953, when he battled with The Wire. That would be a perfect opportunity for some of The Doctor’s knowledge to get transferred to a receptive mind.

What I forgot, is that those events were supposed to have taken place in a different universe to the one Ten is in now according to these stories. So, either readers don’t pay attention to that hiccup, or let’s assume that something of The Wire’s malevolence seeped into this universe, too. Or, the Ninth Doctor and Rose had a parallel problem with her and solved it their own way? Take your pick.

The Amsterdam diamonds that made up Gideon’s nest egg, was inspired by a film I caught a glimpse of a few months back on a weekday afternoon about the efforts of Jews in Amsterdam to get their diamonds away before the Nazis arrive. I can’t remember the name of the film and have no idea where to start looking for it. But it is true that these things happened and it is a plausible reason for the diamonds in Gideon’s possession.

I intended some kind of battle with aliens in which Gideon and Iris helped The Doctor and Louise, but in the end I decided it didn’t need it. The story is about The Doctor and Gideon discovering that they are kindred spirits with a thirst for adventure. It doesn’t need anything else.

Gideon’s decision to give up his wandering life, seems a bit abrupt, but it is the logical thing. He needs to ensure his granddaughter is safe, and without her making the sort of choice The Doctor’s granddaughter made in the end – to leave him and put down her own roots. That was the point of it all. I think it makes a nice, gentle story about Human and Time Lord feelings. If anyone disagrees and thinks there should have been a battle with cybermen or something, just hang on. I’ll get to those.