Subject: Oh, it's pretty obscure.
Author:
Posted on: 2012-09-15 10:58:00 UTC
Like I say, children's TV from at least 20 years ago - possibly twice that, if the ones I watched were reruns. (Unearthly Child, of course, is the first episode ever of Doctor Who - my inconsistant italicisation may have obscured that).
It should happen! And there's no reason they can't shoehorn one into the other - I'm pretty sure a bunch of Poirot episodes had Hastings thrown in where he wasn't - and I actually recall one non-Poirot Christie book having him shoved in...
It's the sort of thing that used to happen quite a lot before the Internet. Probably the most surreal example is the Gallifreyan policeman somewhere in the Fifth Doctor's era... who was played by Colin Baker, the Sixth Doctor. Watching Six shoving Five in prison was really weird... but probably no-one even noticed at the time (well, you know what I mean :P)
hS