Aside from the new Doctor, there was little to distinguish season twelve's first story, Robot, from the type of Doctor Who to which viewers had become accustomed over the previous few years. It was set - like the majority of the Jon Pertwee stories - in near-contemporary England and featured not only the Doctor's established companion Sarah Jane Smith but also Brigadier Lethbridge-Stewart, Sergeant (now Warrant Officer) Benton and the familiar UNIT organisation.
The idea behind this was to reassure viewers that, although the Doctor might have changed, the series itself was still the same. Similarly, although the remainder of the season followed the trend of the later Pertwee stories in moving away from the tried-and-trusted UNIT set-up and into more unfamiliar territory, continued viewer reassurance was provided by the inclusion of a succession of returning monsters.
Robot was the last story of the series' eleventh production block and saw Barry Letts bowing out as producer. His successor, Philip Hinchcliffe, had already been trailing him for some weeks by this point. Letts would however remain on hand to offer comment and advice during the making of the next two stories, The Sontaran Experiment and The Ark in Space (the season's stories again being made out of transmission order), and his influence would be felt throughout the twelfth season as all the scripts had already been commissioned during his time as producer. A large part of the responsibility for shaping the new season, however, fell to new script editor Robert Holmes, who had some strong ideas of his own about the type of stories that the series ought to be featuring.
At only twenty episodes, the twelfth season had been by far the shortest of Doctor Who's history up to this point. The original intention had been that Revenge of the Cybermen would be followed by a further six-part story, but the BBC's programme planners had decided to cut short this run of transmissions and bring forward the next so that Doctor Who's seasons would in future span from autumn to spring, rather than from spring to summer. The twelfth season had done well in the ratings and it was felt that the move to an autumn start would give the BBC an added edge against the rival ITV network in the competition for viewers, particularly as many ITV regions were about to start screening a major new Gerry Anderson series called Space: 1999.
This change of scheduling meant that production of the next batch of twenty-six episodes had to be advanced by some three months to ensure that it would be ready in time for transmission. The division between the twelfth and thirteenth production blocks was consequently more notional than real, as work continued effectively without a break.
The stories of the twelfth season, despite containing some reassuringly traditional elements, had given a clear indication that Doctor Who was undergoing a significant change of style under the new production team of Philip Hinchcliffe and Robert Holmes. Robot, for all its military hardware, gun battles and explosions, had been essentially larger than life, fantasy-based family drama, very much akin to most of the Pertwee-era UNIT tales, but the other stories - particularly The Ark in Space, The Sontaran Experiment and Genesis of the Daleks - had possessed a much more realistic and horrific quality.
Genesis of the Daleks, with its themes of warfare, racial hatred and genetic experimentation, had even provoked complaints from some viewers and from the self-appointed moral watchdogs of the National Viewers and Listeners Association, headed by Mary Whitehouse. This was a trend that would be continued in season thirteen.