The Doctor takes Donna to the Ood-Sphere in the year 4126. Here Ood are bred by the Ood Operations company, to be distributed as pliant servants throughout the worlds of the Earth Empire. But something is going wrong: the Oods' eyes are turning red, precipitating acts of revolt and murder, and ultimately reducing them to a feral state. The time travellers pose as Ood buyers to investigate, even as the odious Mr Halpen arrives to right the corporate ship. The search for answers leads inexorably to the terrible secret hidden for generations within Warehouse 15.

Ever since he became Doctor Who's executive producer in 2003, Russell T Davies had been adamant that the revived programme should not only mine its twentieth-century iteration for ideas, but would offer a steady stream of new concepts as well. During his first two seasons, one of the most popular innovations had been the Ood, a race of alien servitors introduced in Matt Jones' 2006 serial The Impossible Planet / The Satan Pit. Davies quickly decided that the Ood should appear again, and he initially thought that this might occur in 2007's 42. Instead, he decided to defer their return until Season Thirty in 2008.

Hoping to explore the underlying motivation for the Ood's eagerness to please, Davies developed a story idea called Planet Of The Ood. It would reflect upon the reliance which modern Western society placed on overseas sweat shops and battery farms, and the wilful obliviousness which underpinned consumerism. For a time, Davies thought that the Ood narrative might be one of the year's two-part stories, but he soon concluded that it would work better without unnecessary complication. The chief casualty was an extended sequence set in subterranean caverns, in which the Doctor searched for the giant Ood brain. Davies wanted to set Planet Of The Ood on an ice world, because this was an environment which had not yet been attempted in twenty-first-century Doctor Who.

Planet Of The Ood was intended to be the second episode of Season 30

At this point, Planet Of The Ood was intended to be the second episode of Season Thirty. To shepherd it to script form, Davies turned to Keith Temple. The partner of producer Morag Bain, with whom Davies had worked on the family programme Children's Ward, Temple had watched Doctor Who in his youth. In 2006, he sent Davies his script for the forthcoming telefilm Angel Cake, on the strength of which he was invited to a meeting with the production team during the summer. Some thought had been given to assigning Temple a story for Season Twenty-Nine, although this did not come to pass.

In addition to the Ood, Temple planned to revisit another character from The Impossible Planet / The Satan Pit. This was Ida Scott, the science officer played by Claire Rushbrook who had formed a close bond with the Doctor. She would now be a member of an investigative team looking into conditions on the Ood-Sphere, and would be dismayed to discover that her estranged father had become involved with Ood Operations. They would later be reconciled when it was revealed that he was secretly acting on behalf of the Ood. In the end, however, it was agreed that Temple should develop entirely new characters for Planet Of The Ood. Of these, Mr Halpen underwent a more gradual and gruesome process of transformation at one stage. Temple imagined the businessman shedding hair constantly, and ultimately swaddling himself in bandages and dark sunglasses.

When Temple began working on Planet Of The Ood, Davies was still developing the new companion who would join the Doctor for Season Thirty. Since the two most recent TARDIS occupants, Rose Tyler and Martha Jones, had both been young women with a romantic attachment to the Doctor, Davies now sought a completely different dynamic. He had been very fond of the interaction between the Doctor and Donna Noble, the temporary companion played by Catherine Tate in the 2006 Christmas special, The Runaway Bride, and so he was leaning towards a more mature character who would be less of a willing foil for the Time Lord.

Indeed, Davies privately wanted to bring Donna back as an ongoing character, but he assumed that there was no chance that Tate would be available for nine months' filming. She was a high-profile performer in her own right, having already successfully headlined several seasons of her self-titled comedy series, and Davies knew that she was constantly in demand. Instead, Davies decided to craft a new character with Donna-like tendencies. This became Penny Carter, a journalist who would meet the Doctor after discovering that Gary, the boyfriend with whom she resided, was cheating on her. Davies envisaged Penny as having a nagging mother -- possibly named Moira -- and a grandfather who was a more idealistic stargazer. Davies began seriously developing Penny during February 2007.

To Russell T Davies' astonishment, Catherine Tate was interested in reprising Donna Noble throughout Season 30

In early March, he met with Jane Tranter, who had played an instrumental role in Doctor Who's resurrection as the BBC's Controller of Drama Commissioning, and who had recently been elevated to the newly-created position of Head of Fiction. Tranter told Davies that she had spoken with Tate, and raised the possibility of the actress' return to Doctor Who; Davies was considering bringing back all of the Tenth Doctor's companions for the 2008 season finale, and was hoping to include a role for Donna. To his astonishment, Tranter informed him that Tate was actually interested in reprising Donna not just for one story but throughout Season Thirty. Davies' reaction was enthusiastic and, on March 13th, executive producer Julie Gardner formally offered Tate a contract for all thirteen episodes. Tate officially accepted on March 19th. Plans to introduce Penny were immediately scrapped, and the stories currently being written were hastily amended to replace her with Donna. Tate's return to Doctor Who was announced to the press on July 3rd.

Meanwhile, Temple had continued drafting Planet Of The Ood. Its positioning as the season's second episode had now taken on a new importance: since it was a relatively sombre and serious adventure, Davies felt that it would undermine concerns about Donna being too farcical a character to serve as an ongoing companion. By early August, however, Davies had come to feel that Planet Of The Ood had, in fact, become too grim to occupy a slot so early in the transmission schedule. It was decided to interchange it in the running order with The Fires Of Pompeii, making it the year's third episode. Some of Temple's influences were indeed very dark, such as the 2002 horror film 28 Days Later, which inspired the Ood's feral state. On the other hand, the script also included a nod to the fact that Davies' original conception of the Ood had drawn upon the eponymous aliens of the 1964 serial The Sensorites. It was now suggested that the Sense-Sphere of that story and the Ood-Sphere were actually planets in the same solar system.

The first recording block of the new production schedule consisted solely of Voyage Of The Damned, the 2007 Christmas special. Planet Of The Ood was inserted into Block Two, alongside Gareth Roberts' The Unicorn And The Wasp; this pair of episodes would therefore serve as Tate's reintroduction to Doctor Who, almost one year to the day after finishing work on The Runaway Bride. The director would be Graeme Harper, who had most recently worked on 42 and Utopia during the previous season. Cast as one of the Ood Operations representatives was Tariq Jordan whose sister, Yasmin Paige, was starring as Maria Jackson in the spin-off series The Sarah Jane Adventures.

The logistics of the early part of the Season Thirty recording calendar were unusually demanding. The complex Block One included a significant role for world-renowned singer/actress Kylie Minogue, while Block Three -- The Fires Of Pompeii -- featured several days of filming in Italy. To ensure that producer Phil Collinson had sufficient time to oversee the making of these stories, it was decided that his duties on Block Two would be handled by Susie Liggat. She had likewise occupied the producer's chair for the double-banked Human Nature / The Family Of Blood during Season Twenty-Nine. As in that case, Collinson would instead be credited as an executive producer on Planet Of The Ood and The Unicorn And The Wasp.

It wasn't until August 21st that Graeme Harper turned his attention to Planet Of The Ood

Filming for Block Two initially focussed on Roberts' script, so it wasn't until August 21st that Harper turned his attention to the Ood adventure. This was the first of two consecutive days at Doctor Who's regular studio home in Upper Boat, during which the focus was on material in the sales reception area. Shots of an Ood for the advertisement which opened the episode were also captured there on the 21st. The Ood-Sphere plain was actually Trefil Quarry in Trefil, where filming took place on August 23rd. On the 24th and 27th, scenes in the container warehouse were recorded in a hangar at MOD St Athan in the Vale of Glamorgan. August 28th to 31st saw cameras rolling at Aberthaw Cement Works in East Aberthaw, which offered spaces suitable for the Ood cells and the grounds of Ood Operations.

Cast and crew returned to Upper Boat on September 1st. In addition to various effects shots, Harper recorded Bartle's death and the sequence involving Donna inside the Ood container. He also started filming material in Halpen's office; following a break on the Sunday, this work continued on September 3rd. The same day, the BBC confirmed that Doctor Who had been renewed for a thirty-first season -- but revealed that its broadcast would not take place until the spring of 2010, a full year later than anticipated. The twenty or so months following the conclusion of Season Thirty would instead be bridged by a number of specials, with David Tennant remaining as the Doctor, and Davies continuing to serve as the show's executive producer.

It was not typical for the BBC to issue such a detailed and forward-looking glimpse at their plans for a programme. On August 30th, however, the Royal Shakespeare Company had announced that Tennant would be appearing in Hamlet and Love's Labour's Lost throughout the latter half of 2008. Since these dates coincided with the normal start of production on Doctor Who, intense speculation had ensued about the show's future. In fact, the gap between seasons had been planned for quite some time. Although Doctor Who had enjoyed remarkable ratings success since its return in 2005, Davies knew that this interest was not sustainable in the long term, and he felt that a hiatus of sorts after four years on the air would discourage viewers from taking the programme for granted. He also anticipated that he would be leaving Doctor Who around this time, and a year without a full season would facilitate a smoother transition to the next showrunner. Furthermore, Tennant would then be able to return to the theatre -- which he had been eager to do for some time -- without relinquishing his position as Doctor Who's lead actor.

Production on Planet Of The Ood resumed on September 4th, when the Hynix Building in Newport provided the main entrance of Ood Operations. Cast and crew then shifted to the Johnsey Estates in Pontypool, where scenes inside Warehouse 15 were recorded. This work continued to the 5th, alongside an insert of the corridor outside the Ood cells. On September 7th, a pick-up shot of the Doctor and Donna in restraints was taped at Hensol Castle in Hensol. Not recorded during Block Two was the TARDIS scene, because it was belatedly realised that the dialogue would need to be revised to reflect the adventure's later placement in the transmission schedule. Instead, it was deferred to November 16th, when it was taped at Upper Boat together with several additional inserts.

A major edit from Planet Of The Ood was Halpen's appearance at the marketing event infiltrated by the Doctor and Donna. This sequence was meant to provide an early confrontation between the time travellers and the businessman, whose vast wealth initially held some appeal for Donna. The existence of the Friends Of The Ood was also introduced during this exchange. The loss of the material resulted in several other adjustments throughout the episode.

Planet Of The Ood aired on April 19th, 2008, with Doctor Who returning to the 6.20pm timeslot it had occupied two weeks earlier for the season premiere, Partners In Crime. The change was designed to accommodate the return of The National Lottery: 1 Vs 100 later in the evening. Doctor Who continued to be bookended by The Kids Are All Right and I'd Do Anything.

• Doctor Who Magazine Special Edition #20, 19th November 2008, “Episode 3: Planet Of The Ood” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who: The Complete History #58, 2018, “Story 191: Planet Of The Ood”, edited by Mark Wright, Hachette Partworks Ltd.
• Doctor Who: The Writer's Tale by Russell T Davies and Benjamin Cook (2008), BBC Books.