Ex-ter-minate! Ex-ter-minate! You will be ex-ter-minated!! Or rather you would be if you didn't have the only surviving Time Lord in the universe on your side, in the shape of the ever-resourceful and ever-eccentric Doctor.

Since his first incarnation in 1963 (he's now on to the tenth, and those are just the ones we know about), the Doctor has been repelling Daleks, Cybermen, Sea Devils and other cosmic irritants, on behalf of an often blithely ignorant humanity. Just because he likes us. We'll meet some of the Doctor's many assistants over the years, and also find out how that unforgettable theme tune was created.