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.