10 Times Doctor Who Broke Its Own Canon

In science-fiction shows and movies, different coloured blood can be a quick shorthand to demonstrate a character's alien status. Spock in Star Trek bleeds green, as does Ming the Merciless in Flash Gordon.

The Doctor, meanwhile, bleeds an ordinary red. Or hang on, is it blue?

Well, it's blue in State of Decay, in which the Fourth Doctor is bitten by a bat. When he checks his wound, blue blood can clearly be seen on his fingers. The story goes that this was suggested by Tom Baker, who thought that blue blood would reflect the Doctor's lordly status. Producer John Nathan-Turner was apparently annoyed by this bit of Baker tomfoolery, perhaps because it's wildly inconsistent with everything we've seen before or since.

Whether or not there's any truth to this blue blood being a Tom Baker suggestion, there's no escaping the fact that in stories like Death to the Daleks – which aired six years before State of Decay – we are shown the Doctor's very red blood smeared across an oil lamp.

And then, in later stories like The End of Time, the Tenth Doctor's face is covered in little cuts that bleed red after he crashes through a skylight.

So yes, if you cut the Doctor, they bleed red... except for that one time they bled blue. If we're being kind, maybe we can chalk that up to the strange effects of being in E-Space, but in reality, it just doesn't make sense does it.