The Doctor, Jamie and Victoria land on Earth in the near future. A series of catastrophic earthquakes have shaken the planet, resulting in political upheaval. At the same time, the famous scientist Salamander introduces his Suncatcher satellites, which he claims will feed the starving corners of the world. But the Doctor soon discovers a link between the satellites and the earthquakes, uncovering a plot by Salamander -- the Doctor's doppelganger -- to take over the world.

Shortly after completing work on the Season Four finale, The Evil Of The Daleks, David Whitaker was asked to contribute a new set of scripts for Doctor Who's fifth season. The Enemy Of The World was commissioned on July 25th, 1967. A key ingredient of this story would be the introduction of the Doctor's evil double, Salamander; the same sort of idea had been employed for William Hartnell's Doctor in The Massacre Of St Bartholomew's Eve two years earlier. Although Patrick Troughton was disappointed that the plot required Salamander to appear similar to the Doctor rather than allowing him to really modify his regular appearance, he was still glad to have the opportunity to engage in the sort of dressing-up he enjoyed so much.

The Enemy Of The World was the focal point of a series of changes in Doctor Who's key production roles. Most significantly, this would be the final story overseen by producer Innes Lloyd, who had wanted to leave Doctor Who for several months. Lloyd would remain with the BBC until his death on August 23rd, 1991, producing a number of dramas including The Stone Tape, The Snow Goose and Talking Heads. As had been planned for some time, story editor Peter Bryant was pegged as Lloyd's replacement. The identity of Bryant's own successor, however, was in some doubt in the wake of the departure of his assistant, Victor Pemberton, at the end of the summer. The post eventually went to Derrick Sherwin, a longtime actor in theatre, film and television who had more recently begun writing TV plays and for series such as Z Cars and Crossroads. Sherwin was recommended to Bryant by Head of Serials Shaun Sutton.

The director assigned to The Enemy Of The World -- Serial PP -- was Barry Letts. Letts had begun his career as an actor, appearing alongside both Patrick Troughton (in Gunpowder Guy) and Deborah Watling (in HG Wells' Invisible Man). During the Sixties, he began to make a name for himself as a scriptwriter, and had ideas for Doctor Who rejected by former story editor Gerry Davis in late 1966. In the spring of 1967, Letts completed the BBC's internal directors' course and had since been working on series such as Z Cars and The Newcomers.

Letts and Sherwin worked closely together on The Enemy Of The World because the scripts generally ran short and were felt to contain too much dialogue and too little action. In particular, it was Letts who suggested the opening chase sequence featuring a helicopter and a hovercraft, replacing logistically-difficult scenes set at a crowded holiday resort. The names of two of the hovercraft crew were changed from Tibor and Otto to Rod and Curly, respectively -- possibly suggesting that the setting was originally an Eastern European locale, rather than Australia.

Frazer Hines was contracted for The Enemy Of The World on October 25th. A week and a half later, on November 5th, production on the serial began with four days on location at Climping Beach in Littlehampton, West Sussex to capture the story's opening moments. November 9th saw cast and crew travel to Villiers House and Walpole Park in Ealing, for the short scenes of the guards on the fire escape and Jamie in the park. Filming at the Ealing Television Film Studios then took place on November 10th, 11th and 13th. In addition to model shots, the main concern on these days was the climactic TARDIS scene -- the only one to feature the Doctor and Salamander together. Unfortunately, Letts was misinformed as to the best way to record these sequences, a problem compounded when the film became jammed in the camera. This sorely limited the number of shots Letts could use in the finished programme.

As usual, each episode was recorded on successive Saturdays at Lime Grove Studio D. Part one went before the cameras on December 2nd; its production included the use of material filmed for the 1963 James Bond movie From Russia With Love to show the helicopter exploding. The following two weeks saw Frazer Hines' cousin Ian join the cast, playing a guard. Part three, recorded on December 16th, also marked the first use of 625-line videotape in Doctor Who, as opposed to the old 405-line standard. Both Frazer Hines and Deborah Watling were absent from the studio on December 23rd, since neither Jamie nor Victoria appeared in episode four. For the following two weeks, it was Troughton's turn to have a relative take part in the serial -- this time it was his son David's turn to play a guard.

Around the start of 1968, another face joined the Doctor Who production office. With the promotions of Bryant and Sherwin imminent, Sherwin would himself be in need of an assistant story editor. He therefore asked his friend Terrance Dicks to take the position. The Enemy Of The World was completed on January 6th with the recording of episode six. It was at about this time that Troughton agreed to return to Doctor Who for a third season.

At the same time, however, he confessed to Letts that he was finding the programme's gruelling pace of production to be very draining. Troughton particularly disliked the fact that he, Hines and Watling were often required to film inserts for a serial on their days off, or in the midst of studio rehearsals for the previous story in production. Letts remarked that Doctor Who should be scaled back to 26 episode a year (compared to 46 for the fifth recording block), which would permit a week's break between serials for filming and similar matters. Troughton was keen on the idea and suggested it to Bryant, who sought to implement it for the sixth production block.

In addition to the departure of Lloyd at this point, The Enemy Of The World was also the last story overseen by Head of Drama Sydney Newman, the man who had spearheaded the development of Doctor Who in 1963. He had since guided the gestation of series including Adam Adamant Lives! and the soap opera The Newcomers -- both produced by Verity Lambert, whom Newman had selected to be Doctor Who's first producer -- and the acclaimed The Forsyte Saga, produced by his Doctor Who collaborator, Donald Wilson.

His contract having come to an end, Newman left the BBC to work for the Associated British Picture Corporation. Unfortunately, Newman was unable to mount a single film before ABPC was bought out by EMI. He was then apparently offered a new job with the BBC but instead opted to return to his native Canada. There he worked as an advisor to the Canadian Radio and Television Commission and later the federal government, became the chief commissioner of the National Film Board of Canada, and finally served as a consultant for the Canadian Film Development Corporation. Newman eventually returned to England, and in 1986 met with BBC1 Controller Michael Grade to discuss revamping Doctor Who, although nothing would come of this. Newman finally retired to Canada. He died of a heart attack in Toronto, Ontario on October 30th, 1997.

• Doctor Who: The Handbook: The Second Doctor by David J Howe, Mark Stammers and Stephen James Walker (1997), Virgin Publishing, ISBN 0 426 20516 2.
• Doctor Who: The Sixties by David J Howe, Mark Stammers and Stephen James Walker (1992), Virgin Publishing, ISBN 1 85227 420 4.
• Doctor Who Magazine #219, 23rd November 1994, “Archive: The Enemy Of The World” by Andrew Pixley, Marvel Comics UK Ltd.
• Doctor Who Magazine Special Edition #4, 4th June 2003, “Heroes And Villains” by Andrew Pixley, Panini Publishing Ltd.