Slipback by Eric Saward was the first original Doctor Who serial to be produced for radio. It was first broadcast by BBC Radio in the summer of 1985 when the televised series was on hiatus for a year. The broadcast formed part of the three-part children's magazine series Pirate Radio Four which featured two ten-minute episodes per edition.
Colin Baker and Nicola Bryant reprised their TV roles for the production, which also included other cast members. It, along with the earlier Doctor Who and the Pescatons, is considered a forerunner of the later Big Finish Productions audio dramas. It was followed nearly a decade later by two more radio dramas starring Jon Pertwee and in 2007 by a new made-for-radio series for BBC7 (produced by Big Finish) starring Paul McGann.
The Sixth Doctor and Peri share an adventure on board a starship taken over by its dual personality computer, which tries to take the ship back to the dawn of the universe and start life again. Along the way the duo meet a couple of comedy policemen, an art thief and a captain who wants to infect his crew with one of his diseases...
Recovering from a modest hangover, the Doctor hears a voice from his dreams that warns of impending danger for the fabric of time itself. Waking up, the Doctor discovers that illicit time experiments aboard the Vipod Moor, a survey ship taking a census of the galaxy, have pulled the TARDIS out of the vortex. Deciding to investigate further, the Doctor and Peri board the Vipod Moor, but find themselves face-to-face with a raging Maston - a vicious animal that's eating the crew.
Seperated in the confusion, Peri wanders around the ship's corridors while the Doctor happens upon the central computer intelligence that controls the ship and learns that a botched maintenance job has split the computer's consciousness into two personalities - a bubbly public persona and a scheming inner voice.
Having previously scanned the ship's data files, the Inner Voice learned about the galaxy's numerous wars. By developing rudimentary time travel abilities, the Inner Voice embarked on a scheme to take the Vipod Moor back to the Universe's early stages and retroactively impose a new order. To further this, the Inner Voice has used it's limited time travel abilities to materialize a member of the extinct Maston race on board the ship, creating a distraction to keep the crew from noticing the time travel experiments. By telepathically scanning the Doctor's mind, the Inner Voice augments it's time travel devices and primes the ship's engines for a trip back to the early days of the Universe.
The Doctor quickly escapes the inner chamber and reunites with Peri, then dashes into the TARDIS. Gravely concerned that the Inner Voice could massively disrupt history, the Doctor plans to materialize the TARDIS inside the computer's memory core and disable it. However, a member of the Gallifreyan high council urgently contacts the Doctor and warns him to desist, informing him that the web of time already accounts for the Vipod Moor's journey into the past. He explains that the Inner Voice has miscalculated and arrived at the beginning of everything, exploding upon arrival and triggering the Big Bang.
Realizing he nearly aborted the birth of the Universe, the Doctor pilots the TARDIS away from the Vipod Moor, vowing to find a sizeable library and bone up on his knowledge of history. Meanwhile, the Vipod Moor continues on it's fateful journey and the computer's Public Persona decides the Inner Voice's slaughter of the crew was completely unwarranted, activating the ship's self-destruct device, inadvertently insuring the ship will spark the Big Bang - and the rest of the universe - into existence.
- The Doctor - Colin Baker
- Peri Brown - Nicola Bryant
- Computer / Inner Voice - Jane Carr
- Grant - Jon Glover
- Bates / Snatch - Nick Revell
- Maston / Steward / Maintenance Service Drone 934 / Time Lord - Alan Thompson
- Slarn - Valentine Dyall
- Seedle - Ron Pember
- No other individuals were actually credited on-air at broadcast.
- The Doctor and Peri visited the planet Zaurak Minor previously in order to ask for directions. They ended up going to a drinking establishment there and drinking large amounts of the alcoholic beverage Voxnic.
- Peri is believed to be a mini-Migarian.
- Splay-footed Hedrons are found on the planet Vigal Minor.
- Mastons are from Sentimenous Virgo.
- This story was recorded on 10 June 1985 in Studio B11 at Broadcasting House. Valentine Dyall died only fourteen days later.
- This story was broadcast on BBC 4 as part of the Thursday morning magazine programme Pirate Radio Four. Two episodes were broadcast; beginning on 25 July and finishing on 8 August.
- The placement of this story in relation to other Sixth Doctor/Peri adventures is uncertain, since it was produced between Season 22 and Season 23. However, it's generally assumed that it takes place in the gap between those two seasons.
- According to this story, the Vipod Mor is responsible for the Big Bang, yet in TV: Terminus another vessel was responsible for triggering the explosion, and TV: Castrovalva states that it was a "hydrogen in-rush".
- Released as a Silva Screen Records cassette in 1988, it was reissued on CD as part of the BBC Radio Collection on 8 January 2001, and was offered as a promotional giveaway by The Daily Telegraph in 2010.
- Main article: Slipback (novelisation)
Novelised as Slipback by Eric Saward in 1986. It was the first Target Books novelisation not based upon a televised story. The book is notable for not featuring the Doctor or Peri or directly adapting the radio play for its first fifty pages, instead expanding upon characters' backgrounds.
- DisContinuity for Slipback at Tetrapyriarbus - The DisContinuity Guide
- The TARDIS Library - Slipback