From "Doctor Who: The Greatest Show in the Galaxy: Part Three (#25.13)"
So you've always been interested in the Psychic Circus, have you?
Well, yes, of course. I've never been able to visit it before now but I've got all sorts of souvenirs. Copies of all the advertising satellites that have ever been sent out. All the posters. I had a long correspondence with one of the former members too, soon after it started. Although I never got to see the early days, I know it's not as good as it used to be but I'm still terribly interested.