10 Moments That Almost Killed Doctor Who

After the concept of regeneration was introduced, Patrick Troughton played the role for a few wonderful years. Doctor Who had found a means of continuing even after the lead actor departed, so it seemed possible that it could keep going indefinitely.

Unfortunately, the reality of the situation made that less and less likely as Troughton got closer to leaving the show. With ratings dwindling towards the end of his tenure, the BBC seriously considered ending Doctor Who in 1969, with the possibility of replacing it with a revival of Nigel Kneale's Quatermass serials from the 1950s.

Soon though it was decided that Doctor Who would soldier on for at least another year, transitioning into colour television and casting a new Doctor in the form of Jon Pertwee – but even then, its troubles weren't over.

After Pertwee's first year in the role there was yet again talk of binning Doctor Who off, with producer Barry Letts even beginning work on a potential replacement show called Snowy Black, about a displaced Australian cowboy.

This period of uncertainty didn't last long however, with BBC higher-ups determining that Pertwee's first season had performed well enough for the show to continue.