Partners In Crime (Doctor Who)
"Partners in Crime" features the return of three recurring characters: Jacqueline King reprises her role as Sylvia Noble from "The Runaway Bride"; Bernard Cribbins reprises his role as Wilfred Mott from "Voyage of the Damned", to replace the character of Geoff Noble after actor Howard Attfield died; and Billie Piper briefly reprises her role as Rose Tyler for the first time since the second series' finale "Doomsday" (2006), in a scene that was not included in preview showings.
The episode was received positively by critics. Most reviewers praised the visual effects used to create the Adipose and Tate's subdued acting in comparison to "The Runaway Bride"; Donna was changed from a "shouting fishwife" to a more emotional person when she became a full-time companion. Critics were polarised over the episode's plot: opinion on executive producer Russell T Davies' writing ranged from "pure pleasure" to "the back of a fag packet".
Plot
Donna Noble finds herself regretting her decision to decline the Tenth Doctor's invitation to travel in the TARDIS. She has started investigating conspiracy theories, such as certain bees disappearing in the hope that she will find him again. The Doctor and Donna, neither one aware of the other's involvement, both investigate Adipose Industries, which is marketing a special diet pill to the people of London. They find that the pills use latent body fat to parthenogenetically create small white aliens called Adipose that spawn at night and leave the host's body. The Doctor and Donna separately infiltrate the offices of Adipose Industries, each unaware that the other is there. As they explore the building, they suddenly encounter each other through opposite windows in an office. They are confronted by Miss Foster, an alien who is using Britain's overweight population to create the Adipose babies for the Adiposian First Family. Miss Foster pursues the Doctor and Donna around the building, finally catching them in an office. She tells the Doctor that the Adipose lost their breeding planet and hired Miss Foster to find a replacement. The Doctor uses Miss Foster's sonic pen and his sonic screwdriver to create a diversion and escape.
Miss Foster accelerates her plans, knowing that the Doctor will attempt to stop her. Throughout London, the Adipose begin to spawn and soon number several thousand. The Doctor and Donna prevent total emergency parthenogenesis from occurring, which would have killed those who had taken the pill, and the remainder of the young Adipose make their way to Adipose Industries. The Adiposian First Family arrive in a spaceship and begin collecting their young. The Doctor tries to warn Miss Foster about her safety, but she disregards him and is killed when the Adipose drops her from their transport beam to her death, to cover their unsanctioned seeding efforts.
Donna accepts the Doctor's original offer to travel in the TARDIS. Donna makes a detour to leave her car keys in a litter bin, telling her mother Sylvia to collect them later. While there, she meets a blonde woman and asks her to help Sylvia find the keys. The woman turns out to be Rose Tyler, who fades from view as she walks away from the area. Donna asks the Doctor to fly the TARDIS past Donna's grandfather Wilfred Mott, who is watching the night sky through a telescope. Donna waves Wilfred off inside the TARDIS.
Production
Casting
"Partners in Crime" features several actors returning to the series. Catherine Tate was offered the opportunity to return as Donna Noble during lunch with executive producer Julie Gardner. Tate, who expected Gardner would ask about appearing in a biopic, later admitted it was "the furthest thing from [her] mind". Tate's return was controversial amongst Doctor Who fans; the criticism she received was compared to Daniel Craig after he was cast as James Bond. Howard Attfield, who appeared as Donna's father Geoff in "The Runaway Bride", filmed several scenes for this episode, but died before his scenes for the remainder of the season were completed. The producers retired his character out of respect, and dedicated him in the closing credits for the episode. Producer Phil Collinson suggested transferring his traits to the unrelated character Stan Mott from "Voyage of the Damned", and rewriting his role as Donna's grandfather. Executive producers Russell T Davies and Gardner liked the idea and recalled Bernard Cribbins to the role to re-film Attfield's scenes, with the character renamed as Wilfred—a name Davies favoured for Donna's grandfather—in time for the credits of "Voyage of the Damned" to be changed.
Writing
I see her as a slightly warped Mary Poppins. She's quite austere. She's a strong woman. When I first read the script, I thought, oh, well, of course she's a baddie... but the more I read it, I thought, 'No, she's doing what she's doing for legitimate reasons.'
Davies took a different approach while writing the episode. David Tennant and Sarah Lancashire noted the character of Miss Foster had good intentions but was morally ambiguous. The premise of the Adipose pill was equally ambiguous with rare side-effects, but was a "win-win situation" for anyone involved. Davies based the character of Miss Foster on Supernanny star Jo Frost and Argentine philanthropist and politician Eva Perón, and Lancashire compared her character to Mary Poppins. The Adipose are a different style to regular Doctor Who villains; antagonists such as Lazarus in "The Lazarus Experiment" or the werewolf in "Tooth and Claw" were singular monsters designed to scare the audience; the Adipose were written as "cute" to provide a "bizarre [and] surreal" experience.
Davies made some changes to Donna's character. The character was "rounded ... out from being a shouting fishwife to someone who's quite vulnerable and emotional". Donna was written to provide a "caustic" and "grown-up" attitude towards the Doctor, in opposition to Rose and Martha, who fell in love with him. Tate considered Donna to be more equal to the Doctor because her character did not romanticise him, allowing her to question his morality more easily.