Quote Originally Posted by Sunken Valley View Post
True, but there does, under the requirements of the bbc, have to be an extraterrestrial threat every episode. Hence the addition of the reapers to Father's Day and the handbots being lethal in GWW.
First, do you have a source for that assertion? True, there haven't been any instance of purely mundane threats since 1982, and before that none since very early in the 2nd Doctor's run, but I'm not aware that it's a set policy by the BBC.

Second, technically neither Silurians nor gangers are extraterrestrial. And maybe not the Silence, either, but that's not quite clear. And that's just limiting it to threats faced by the 11th Doctor. But if your assertion is true, I guess all 3 and other, earlier examples, might be close enough.