It's all over the doctorwhoforum at the moment, it was the latter, is what he seemed to say (I believe it's the current Torchwood magazine). Again, I'll happily PRAISE GDL for this, and it doesn't surprise me that it was his idea, but the simple fact that that sort of thing has to come from the actors is fucking scary. They're VERY LUCKY to have someone like GDL, and to have had someone like Burn who obviously put a bit of thought into what the hell is going on in their character's heads, because the writers certainly don't seem to, and that's shocking.