10 Things That Make No Sense In Doctor Who

The Doctor's missing heart isn't the only time their biology has made no sense.

Whether they're getting into a scrap - or just gathering cuts and bruises over the course of their heroics - every time the Doctor is wounded, the character's blood is red (see the Tenth Doctor in The End Of Time, above), just like an ordinary human's.

But oddly, there's one occasion in the show where this isn't actually true.

The first episode of the Fourth Doctor serial State Of Decay ends with the Doctor getting chomped on by a bat. He touches the wound and gets some blood on his fingers, and there's a quick shot where we see that this blood, surprisingly... is blue?

This is never addressed, mentioned, or seen from again, and from here on out, the Doctor's blood is a bog-standard shade of red. So what happened here?

Well, word is that Tom Baker felt that the Doctor - as a member of the Gallifreyan aristocracy - should have blue blood, signifying his importance (in real-world history, people of noble birth are sometimes referred to as "blue-blooded").

It's also said that showrunner John Nathan-Turner wasn't told about this, and that he was cheesed off when he found out - which is why the scene is edited in such a way to mask the blood as much as possible.

Whether or not that story is true, the fact is that the Doctor has always had red blood - both before State Of Decay, and after. So let's just forget this happened, shall we?