On the planet Dido in the year 2493, the Doctor, Ian and Barbara discover the indigenous civilisation has been eradicated. Furthermore, the entire crew of a crashed Earth spaceship has been murdered, with the exception of the crippled Bennett and the orphan Vicki, who are being terrorised by the monstrous Koquillion. But who is Koquillion, and what are his true motives?

Doctor Who producer Verity Lambert and story editor David Whitaker had planned since at least May 1964 to make changes to their lead cast should the programme be renewed for a second recording block. When, on August 14th, Chief of Programmes Donald Baverstock finally granted Lambert thirteen more weeks of Doctor Who, Lambert quickly set about finalising plans to write out Carole Ann Ford's Susan in the concluding episode of The Dalek Invasion Of Earth, the last story of the first production block. Her replacement would be the freedom fighter Jenny introduced in the same story.

In the wake of Doctor Who's renewal, however, Lambert was confronted by various contractual demands from her remaining stars. This cast a shroud of uncertainty over the programme's future yet again. Baverstock was also unhappy at the proposition of a change in the main cast, and suggested that Doctor Who might instead be replaced altogether by a new science-fiction series following the transmission of The Dalek Invasion Of Earth.

Consequently, by August 20th, Lambert had decided not to install Jenny as the new companion, although Ford would still exit the programme as previously planned. Instead, the new companion -- who, like Susan, would be a teenaged girl -- would debut in the first serial of the new recording block. This gave Lambert time to work out the issues raised by William Hartnell, William Russell and Jacqueline Hill. In the process of settling their contracts, Lambert was also able to get a guarantee of another thirteen weeks from Baverstock; talk of Doctor Who being cancelled in favour of a different show was put to rest entirely.

By this time, Whitaker had decided to leave his post as Doctor Who's story editor as of October 31st; he would be replaced by Dennis Spooner, who had already scribed The Reign Of Terror and who was now working on the second story of the new recording block, The Romans. As a coda to his regular involvement in Doctor Who, however, Whitaker (who had already authored Inside The Spaceship) agreed to write a two-part adventure to introduce the new companion. Although this would be the first serial made as part of the second production block, it would be the third story of Doctor Who's new season, both Planet Of Giants and The Dalek Invasion Of Earth having been held over.

Names considered initially by Whitaker for the new character included Valerie and Millie. The latter was inspired by pop star Millie Small, but was rejected because of its association with well-known comedian Millicent Martin. Whitaker then settled on the name Tanni and so this story -- assigned the code Serial L -- was given the working title “Tanni”. It was not formally commissioned until November 1st, following Whitaker's departure from the show.

On September 14th, camera tests for the part of Tanni were held, with both Maureen O'Brien and Denise Upson present; O'Brien would win the role. After working toward a teaching diploma, O'Brien had recently helped found the Everyman Theatre in Liverpool. She was encouraged to audition for Doctor Who by a former teacher, Harry Moore, who now worked as a producer at the BBC. O'Brien was reticent about accepting the regular role, having not really considered television as a likely career move. She eventually took the job in part to be with her boyfriend, Michael, who was living in London; they would later marry. O'Brien was contracted for her introductory story, as well as The Romans and The Web Planet, on October 9th.

Meanwhile, the new companion continued to be developed over the break in production during the autumn of 1964. The name Tanni was discarded, and by November 12th, Lambert's preference was Lukki (pronounced “Lucky”). The day before, O'Brien was introduced to the press in a photocall. Just over a week later, on November 20th, the character had acquired her permanent name of Vicki. The serial's title was amended to The Rescue.

Model filming for The Rescue was carried out at the Ealing Television Film Studios on November 16th and 17th. The director assigned to the serial was Christopher Barry, who had handled some episodes of The Daleks a year earlier. As with the first production block, the new group of episodes would each be recorded on consecutive Fridays, with Doctor Who returning to its new studio home of Riverside 1. The first installment of The Rescue, The Powerful Enemy, was taped on December 4th, reuniting Hartnell, Russell and Hill after a six-week break. O'Brien was initially worried about joining such a well-established ensemble but was reassured following a visit by Carole Ann Ford, who dropped by on the first day of rehearsals to wish the new castmember good luck.

Episode two, Desperate Measures, was taped on December 11th. An accident occurred during the sequence in which Barbara shoots Sandy, the sand monster, when the flash charge in Barbara's pistol went off too soon, hurting Jacqueline Hill's face and badly startling the actress. When the scene was remounted, a flash charge was detonated on the set near Sandy instead of in the gun itself.

The Rescue was the first story to make use of an alias for one of its castmembers in order to avoid spoiling surprises in the plot. Specifically, Koquillion was listed as being played by “Sydney Wilson” and not Ray Barrett at the end of The Powerful Enemy, in order to preserve the secret of Bennett's dual identity. The pseudonym was derived from the names the Heads of Drama and Serials -- respectively, Sydney Newman and Donald Wilson. Both men were driving forces behind Doctor Who during its formative period. The practice of utilising aliases in the end credits would be employed sporadically in ensuing seasons.

Although The Dalek Invasion Of Earth had drawn record audiences for Doctor Who, The Rescue managed to better it. On January 9th, 1965, Desperate Measures became the first Doctor Who episode to reach eighth place amongst programmes for the week. It would not be the last time Doctor Who would attain such lofty heights.

• Doctor Who: The Handbook: The First Doctor by David J Howe, Mark Stammers and Stephen James Walker (1994), Virgin Publishing, ISBN 0 426 20430 1.
• 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 #325, 8th Jan 2003, “Archive: The Rescue” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who Magazine Special Edition #7, 12th May 2004, “I'm Into Something Good” by Andrew Pixley, Panini Publishing Ltd.