Charlie Brooker's Screen Wipe is fucking brilliant. And the Xmas special was fantastic - from lovely old Christmas BBC idents, to his steadfast refusal to admit Victor Lewis-Smith exists (a clever way of admitting his influence), the only bad thing was the constant cropping of 4:3 material to widescreen. You'd expect it from some shows; but it seems an anomaly for someone who loves old telly as much as Brooker clearly does.

But there's one thing that really intrigued me about this episode. He showed some lovely clips of old Noel's Christmas Presents, with some beautifully shot linking sequences that put this year's ITV Phillip Schofield effort to shame. But Brooker makes the link between Noel's show doing The 12 Days of Christmas, and Knowing Me Knowing Yule doing the same. Sure, Noel's looked more rather more expensive, but it was clear that it was a direct influence.

And this is the weird thing. Stuff like Knowing Me, Knowing Yule gets put out on DVD, where it can be remembered. There's just no way Noel's Christmas Presents would be. Now, if you're an archive TV fan, you can find copies - but to the general public, who aren't deranged enough to do that, slowly but surely the specific reference is lost, even though it's widely known that there's a lot of Edmonds in Partridge.

That doesn't mean Alan Partridge becomes meaningless, obviously, or even that it hurts the show. He still works as a parody of a certain kind of television presenter; indeed, perhaps more importantly, he still works as a character on his own terms. But as the specific reference is lost, a little bit of the programme's context is taken away. And what's perhaps most intriguing is that we're not talking about a programme from decades ago - we're only talking about the 90s, here.

It's amazing how easy references become buried in time. And it's easy to forget that DVDs don't really represent television. There's so much material that is completely commercially unviable, and would never be released. But it's interesting to note that whilst parodies of certain types of television programme often make it onto DVD, and so live on... the original programmes themselves usually don't.