The TARDIS lands on the planet Karfel, which is under the sway of the mysterious Borad. The Borad wields the power of a time tunnel called the Timelash, through which foes are banished, never to return. When the Borad kills the nominal ruler, Renis, and installs the scheming Tekker in his place, Renis' daughter Vena steals a vital amulet and throws herself into the Timelash. With Peri held prisoner, the Doctor agrees to follow Vena's trail, and he finds her in the care of a young writer named Herbert in nineteenth-century England. The Doctor convinces Vena to return to Karfel... but neither Tekker nor the Borad is to be trusted.

Glen McCoy was still establishing his credentials as a television scriptwriter when he decided to pitch an idea for Doctor Who. Having watched the programme with his three-year-old son, he wanted to challenge what he perceived to be a lack of inventiveness in the storylines. McCoy recalled early episodes of Doctor Who from his childhood, and he was guided by these memories as he formulated a proposal involving the Daleks. It was submitted to the Doctor Who production office in early 1983, only to be rejected by script editor Eric Saward. However, Saward told McCoy that he might reconsider if the pitch was revised to omit the Daleks. The writer complied, and a storyline was commissioned on May 11th under the title Timelash.

The narrative's central hook was the appearance of a young HG Wells, referred to as “Herbert” until the end of the story to preserve the surprise of his identity. Wells was a pioneer of science-fiction in the nineteenth century, and McCoy incorporated a number of references to his oeuvre. Most obvious were the connections to Wells' 1895 work The Time Machine: the Eloi girl Weena suggested Vena's name, the monstrous Morlocks became the Morlox, and of course the TARDIS itself owed a great debt to the Wells novel. Other inspirations were 1896's The Island Of Doctor Moreau, which prompted the hybrid nature of the Borad, and the 1897 novella The Invisible Man, with the Doctor essentially becoming invisible using the Kontron crystals.

Glen McCoy was instructed to ensure that Timelash could be made inexpensively

Saward was happy with the result, and McCoy was asked to script Episode One on June 24th; at this point, Timelash was intended to consist of four twenty-five-minute episodes. McCoy delivered his script in June, after which four months elapsed without further communication from the Doctor Who production office. After inquiries from McCoy's agent, the remainder of Timelash was finally commissioned on November 23rd. By now, however, it had been decided that Season Twenty-Two would embrace a new forty-five-minute format, and so McCoy would have to revise Timelash appropriately. He was also instructed to ensure that the serial could be made inexpensively, which forced the elimination of a large-scale Gurdel invasion from the narrative.

As the serial developed during 1984, Saward became concerned about the quality of McCoy's scripts, especially in light of his limited experience in television. On the other hand, producer John Nathan-Turner was reluctant to waste the fees already paid to McCoy, and argued against dropping Timelash. Season Twenty-Two had already suffered one casualty, when Pat Mills' “The Space Whale” was abandoned at a late date. In fact, Timelash would be occupying the year's penultimate slot, which had become vacant when Vengeance On Varos was brought forward to take the place of “The Space Whale”.

Instead, Saward made a variety of amendments to McCoy's scripts. For example, Maylin Tekker did not experience a change of heart in McCoy's original script, and was instead in the process of shooting the Doctor when he was murdered by the Borad. Bizarrely, towards the end of the serial, McCoy had the Borad reject his desire to mate with Peri, because he could now create as many clones of himself as he wished; Saward deleted this entirely. The Gurdels were renamed the Bandrils, while Maylin Renis had previously been known as Maylin Vena, suggesting that McCoy intended “Vena” to be a family name. Saward took out the scripted explanation for the destruction of the Bandril missile -- that the bendalypse was neutralised via contact with the time field of the TARDIS -- and replaced it with the Doctor's vague assurance that he would explain it to Peri later... and off-screen. McCoy had depicted the action as unfolding over the course of multiple days, but Saward pruned this down to a matter of hours.

An unusual conceit of McCoy's storyline was the idea that the Doctor had visited Karfel during an earlier incarnation. In the original scripts, Katz's locket was to contain a reference to Gallifrey, which Peri identified as the Doctor's home planet in order to gain Sezon's trust. Saward rewrote this material to instead have Peri identify a picture of one of the Doctor's former companions. Initially, it was the First Doctor who had been present on Karfel, and the locket held a portrait of his granddaughter, Susan. Once it was agreed to use the Third Doctor for this purpose, the image was changed to depict Jo Grant; a publicity still taken during the making of 1972's Day Of The Daleks was ultimately employed.

Paul Darrow wanted to play Tekker archly, with a pronounced hump

Timelash was assigned to director Pennant Roberts, who had last worked on the previous season's Warriors Of The Deep. He was able to convince Paul Darrow -- who had starred in the BBC's more adult-oriented science-fiction drama, Blake's 7 -- to portray Tekker. Seeing something of King Richard III in Tekker, Darrow wanted to play the role archly, with a pronounced hump, but Nathan-Turner prevailed upon him to rein in the campier excesses of his approach. Roberts also decided to cast an actress in the role of Aram, who had been written as male; the director often strove to find additional roles for women in his productions. A late change was the decision to represent the Bandril ambassador by a hand puppet -- voiced by Martin Gower, who also played Councillor Tyheer -- as another cost-saving move.

Part of Nathan-Turner's motivation in assigning Roberts to Timelash was his hope that the director's substantial experience would help compensate for any shortcomings in McCoy's scripts. However, Roberts was dismayed by what he deemed to be a substandard piece of writing and, although Saward was busy with his own scripts for the season finale, Revelation Of The Daleks, Roberts prevailed upon him to perform further revisions on Timelash. Of particular concern was the hostile nature of the Doctor and Peri's relationship, and the Doctor's generally mean-spirited attitude; Saward would soften much of their dialogue. Both men were worried that Episode One would overrun while Episode Two would be too short, so Saward attempted to rebalance the scripts to account for the disparity.

Timelash was recorded in two three-day blocks. The first session spanned December 4th to 6th and took place at BBC Television Centre Studio 4 in White City, London. Work on the initial day concentrated on the sets for the TARDIS and the reception chamber. The next two days were primarily concerned with scenes in the inner sanctum and the corridors; some material in the detention room was also taped on the last day. The portrait of the Third Doctor hidden in the inner sanctum was painted by an American fan named Gail Bennett, who had come to the attention of the production team after creating a series of Doctor Who art cards. For reference, Bennett used an image of Jon Pertwee from 1974's Invasion Of The Dinosaurs.

Roberts' team relocated to TC8 for the second block, which ran from December 19th to 21st. The session started with the remaining action in the detention room, together with sequences in Herbert's cabin, the tunnels, the rebel camp and the power vault. Work in the Borad's chamber began on the middle day and continued to the final day of the block, when there was also further taping on the tunnel sets, as well as in the Timelash itself. Modelwork rounded off Roberts' agenda.

It was determined that Episode 1 was seven minutes too long, while Episode 2 underran by four minutes

Even before recording ended, it became apparent to Roberts that Saward's efforts to remedy the lengths of the two episodes had been unsuccessful. It was ultimately determined that Episode One was seven minutes too long, while Episode Two underran by four minutes. Roberts suggested simply shifting the cliffhanger back to the Guardoliers' attack on the rebels, and inserting reaction shots to imply that Peri had been killed instead of Katz. However, Nathan-Turner was determined that Episode One should end with the Doctor about to be thrown into the Timelash, and so he rejected Roberts' proposal.

Instead, some of the material involving Peri being taken to the Morlox cave would be shifted back to Episode Two. Minor trims would then shorten the first installment to its proper duration. To prop up the concluding episode, Nathan-Turner authorised a remount in order to record extensions to its two TARDIS scenes. Saward wrote the additional material and David Chandler, who played Herbert, was rehired. The new footage was taped in TC8 on January 30th, 1985, at the start of the second studio block for Revelation Of The Daleks. Bryant disliked the added material, while Roberts was unhappy with Timelash as a whole, blaming both McCoy's scripts and the new forty-five-minute format. It would prove to be his final Doctor Who serial.

• Doctor Who Magazine #231, 25th October 1995, “Archive: Timelash” by Andrew Pixley, Marvel Comics UK Ltd.
• Doctor Who Magazine Special Edition #3, 22nd January 2003, “Everything Must Change” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who: The Complete History #41, 2018, “Story 141: Timelash”, edited by John Ainsworth, Hachette Partworks Ltd.
• Doctor Who: The Eighties by David J Howe, Mark Stammers and Stephen James Walker (1996), Virgin Publishing.
• Doctor Who: The Handbook: The Sixth Doctor by David J Howe, Mark Stammers and Stephen James Walker (1993), Virgin Publishing.
• In·Vision #83, March 1999, “Production” edited by Anthony Brown, Cybermark Services.