The TARDIS lands on a space beacon, which is in the process of being stolen by the cruel pirate Caven, who wants to harvest its valuable argonite. The Doctor, Jamie and Zoe are rescued by an aging pioneer named Milo Clancey. However, General Hermack of the Space Corps suspects Clancey of being the pirates' ringleader. Clancey flees to the planet Ta, home of the Issigri Mining Company, which is run by the daughter of his late business partner. But Ta is also the location of Caven's secret lair -- and the time travellers must uncover the connection between the pirates and Madeleine Issigri before it is too late.

The story designated with Serial YY as its production code, destined for the latter part of Doctor Who's sixth season, was originally intended to be Robert Holmes' The Krotons. However, that story was brought forward in the schedule to take the place of the abandoned “The Prison In Space”. On October 22nd, 1968, shortly before recording began on The Krotons, Holmes submitted a new idea entitled “The Aliens In The Blood”. When it was rejected, an undeterred Holmes developed a new proposal, which he envisaged as a futuristic homage to the Western genre. This proved more to the liking of script editor Terrance Dicks, and a storyline was commissioned under the title of The Space Pirates on November 9th. It was planned to be a six-part adventure, although Holmes would later recall that he had originally intended for there to be only four episodes.

At this point, although Peter Bryant was still Doctor Who's producer, he was preparing to move over to Special Project Air and was also suffering from a bout of ill health. As such, Derrick Sherwin -- who had previously been the programme's story editor -- was taking on more and more of Bryant's responsibilities, with the expectation of eventually replacing him completely. It was also around this time that Dicks acquired an assistant in the form of Trevor Ray. However, as work began on The Space Pirates, Dicks was absorbed with the serials which would be made on either side of it: he was rewriting the last two-thirds of The Seeds Of Death, and collaborating with Malcolm Hulke on the massive ten-part The War Games, which would be both the season finale and the last story of Patrick Troughton's tenure as the Doctor. With Ray unprepared to take over as script editor, it was agreed that Sherwin would return to his former post for The Space Pirates.

Assistant floor manager John Turner would become Doctor Who's producer a decade later

On November 20th, Frazer Hines was contracted for The Space Pirates and The War Games. Despite concerns that the Doctor, Jamie and Zoe were not featured enough in Holmes' storyline, the scripts for The Space Pirates were commissioned on December 3rd. Early in the new year, director Michael Hart joined the production; this would be his only Doctor Who serial. Amongst his crew was an assistant floor manager named John Turner; more commonly credited as John Nathan-Turner, he would become Doctor Who's producer a decade later.

One problem Hart had to navigate was the decision to schedule an extra week of pre-filming for The War Games, in light of its extraordinary length. For Hart, this meant that the regular cast would be unavailable when the concluding installment of The Space Pirates was taped in the studio, since the two sets of recording dates would coincide. It was agreed that all of the material involving the Doctor and his companions in Episode Six would instead be pre-filmed. Patrick Troughton, Frazer Hines and Wendy Padbury were all issued additional contracts for this work on January 23rd, 1969. To simplify Episode Six in light of these unusual circumstances, Madeleine Issigri's role was expanded to have her appear on monitors to speak with the pirates and, later, Hermack, instead of the Doctor.

Filming for The Space Pirates began on February 7th at the BBC Television Film Studios in Ealing, London. The first day was principally concerned with scenes on the beacon, using Kirby wires to give an impression of weightlessness; it appears that some of this material may have been remounted on the 10th. The bulk of February 10th to 14th was taken up with filming the Episode Six sequences featuring the regular cast. Unfortunately, a portion of the film shot on the 14th was damaged during processing, apparently affecting some of the material set in the atomic fuel store. A remount was held at Ealing on February 19th, requiring only Troughton's presence. The serial's model shots, meanwhile, were completed by the Bowie Group in Slough, Berkshire. With Hart too busy working on the rest of The Space Pirates, special effects designer John Wood supervised this element of the recording.

As usual, each installment of The Space Pirates was recorded on consecutive Fridays. Episode One went before the cameras on February 21st, at Doctor Who's regular home of Lime Grove Studio D in Shepherd's Bush, London. During the following week, on February 24th, the BBC announced that Wendy Padbury would be leaving Doctor Who at the end of the season. Bryant and Sherwin had hoped to persuade her to stay for another year, but the actress had now decided to depart alongside Troughton and Hines.

Episode 1 would be the last time Lime Grove Studios played host to Doctor Who

Episode One would be the last time Lime Grove played host to Doctor Who, marking the end of an association which dated back to the very first serial, 100,000 BC. The programme's new production home would now be the more modern BBC Television Centre in White City, London, where it had occasionally been made in the past. Most of the remaining episodes were scheduled to be taped in Studio 4, although Episode Five -- recorded on March 21st -- was housed in TC6. Because of the pre-filming arrangement involving The War Games, only the guest cast was present for the recording of Episode Six on March 28th.

The penultimate story of the Troughton era was also the last to feature a credit for producer Peter Bryant, although he would continue to share the job with Sherwin until October. While it was thought, for a time, that he would rejoin Sherwin on Doctor Who following his work on Special Project Air, he was soon reassigned to the detective series Paul Temple, a high-profile German co-production which was in deep distress. The broadcast of The Space Pirates Episode Six on April 12th also saw a small change to the BBC's Saturday evening schedule. For the last three months, Doctor Who had been followed by a news update, a Tom And Jerry cartoon short, and then the sitcom Here's Lucy, but the animated programme was now dropped.

• Doctor Who Magazine #242, 28th August 1996, “Archive: The Space Pirates” by Andrew Pixley, Panini UK Ltd.
• Doctor Who Magazine Special Edition #4, 4th June 2003, “Paradise Lost” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who: The Complete History #14, 2018, “Story 49: The Space Pirates”, edited by John Ainsworth, Hachette Partworks Ltd.
• Doctor Who: The Handbook: The Second Doctor by David J Howe, Mark Stammers and Stephen James Walker (1997), Virgin Publishing.
• Doctor Who: The Sixties by David J Howe, Mark Stammers and Stephen James Walker (1992), Virgin Publishing.