The season consisted of six serials and thirteen episodes. With this season the BBC experimented with the format of the series, reducing the number of episodes to thirteen, but making each episode forty-five minutes long. The experiment did not result in improved ratings and at the end of the season the BBC announced it was cancelling the series; uproar from fans resulted in the BBC changing its mind and putting the series on an eighteen month hiatus instead. This season is notable for featuring the final appearance of Patrick Troughton as the beloved Second Doctor, in a storyline that gave rise to a popular fan theory known as Season 6B.