10 Things That Must NEVER Happen In Doctor Who

Nothing taps into the fundamental appeal of Doctor Who quite like the image of a quaint British police box standing on an alien landscape.

Now, imagine if the TARDIS' chameleonic powers made it invisible, or made it look like a typical flying saucer. Boring, right?

This is why the original pitch documents for Doctor Who emphasised the need for the TARDIS to disguise itself as something everyday. Sydney Newman didn't want Doctor Who to be like every other sci-fi show, and by finally settling on a police box, they established the show's unique iconography.

Doctor Who isn't Star Trek. It doesn't have sleek and sterile spaceships, that's never been its deal. It's always been a show that combines the humdrum with the extraordinary. A battered old police box that can travel anywhere in time and space has always been emblematic of its core ethos.

Changing the TARDIS into an elaborate time machine like the one dreamed up by HG Wells would take away Doctor Who's ramshackle charm. So too would removing its unique wheezing, groaning sound.

That's right River, we will absolutely be leaving the brakes on!