The Stolen Earth - Production - Daleks

Daleks

"The Stolen Earth" is the first appearance of the Daleks since "Evolution of the Daleks", which was filmed eighteen months prior to the episode; consequently, the prop controllers experienced difficulty re-adapting to their roles. Davies's inclusion of the Daleks as part of the crossover was intended to create a "charged atmosphere" for the protagonists: Jack was killed by the Daleks; Rose and Martha were present at two of their apparent extinctions; and Sarah was present at their creation. The animatronic of the Dalek mutant had to be recreated for the episode, because the previous prop that was used in "Dalek" and "The Parting of the Ways" was irreversibly damaged by water when the latter was filmed. "The Stolen Earth" features two new variants of Daleks: the Supreme Dalek, coloured red as an allusion to the Peter Cushing film Dr. Who and the Daleks; and the partially destroyed Dalek Caan. Caan was described in the shooting script as:

...open, gutted, and melted, its harsh lines now curved and warped... in the middle of the warped, open shell sits a Dalek Mutant, tentacles stirring. This creature is more distorted than ever, its skin bubbled. One blind eye staring out; voice ancient, sing-song, mad. —Russell T Davies, Shooting script for "The Stolen Earth". Transcribed by Andrew Pixley of Doctor Who Magazine.

Voice actor Nicholas Briggs adopted a different voice for each model: he adopted a grandiose voice for the Supreme Dalek to fit his perception of the character as egotistical; and he adopted a sing-song voice for Caan to reflect the character's insanity as a result of entering the Time War. Briggs justified his interpretation of Caan by explaining that " can't tell when he's happy or sad, his emphasis is very strange and he finds things funny when things aren't funny", creating a soothsayer personality with an "almost pure" mind. An expanded theory was published in Briggs' interview with Doctor Who Magazine in July 2008:

My theory on Caan is that being sucked through the Time War and blown out the other end has kind of reverse-wired—or random-wired—his brain, so all his neurons are firing in constantly changing, random, insane ways. That's why he doesn't really know what's funny or serious. He just knows the truth, and it blurts out in this odd, cryptic way. I think he's frozen in a moment of excrutiating ecstasy. When any emotion surges up inside him, it makes him laugh, whether its appropriate or not. —Nicholas Briggs, Doctor Who Magazine issue 398

Briggs' portrayal was well-received by the production team: Graeme Harper "loved Caan's giggling" and requested "more ... on every take"; and Davies described Caan as "the creepiest Dalek yet". The finale also introduced minor changes to the Daleks: the characteristic Dalek "plunger" was replaced with a gear mechanism for scenes that featured Davros' guard: the mechanism is used to control Dalek machinery aboard the Dalek flagship Crucible more efficiently; and the Dalek eyestalk exhibits a minuscule twitch in scenes, a characteristic added by Graeme Harper to make them appear cautious and "on-edge".