The Poison Sky

192b – "The Poison Sky"
Doctor Who episode
250px The Valiant firing at the ATMOS Factory.
Cast
Doctor David Tennant (Tenth Doctor)
Companions Catherine Tate (Donna Noble) Freema Agyeman (Martha Jones)
Others Billie Piper – Rose Tyler Christopher Ryan – General Staal Rupert Holliday-Evans – Colonel Mace Bridget Hodson – Captain Price Dan Starkey – Commander Skorr Bernard Cribbins – Wilfred Mott Jacqueline King – Sylvia Noble Ryan Sampson – Luke Rattigan Christian Cooke – Ross Jenkins Clive Standen – Private Harris Wesley Theobald – Private Gray Meryl Fernandes – Female Student Leeshon Alexander – Male Student Kirsty Wark – Herself Lachele Carl – US Newsreader Jack Steed – Lieutenant Skree
Production
Writer	Helen Raynor
Director	Douglas Mackinnon
Script editor	Nikki Smith
Producer	Susie Liggat
Executive producer(s)	Russell T Davies Julie Gardner Phil Collinson
Incidental music composer	Murray Gold
Production code	4.5
Series	Series 4
Length	2nd of 2-part story, 45 minutes
Originally broadcast	3 May 2008
Chronology
← Preceded by Followed by → "The Sontaran Stratagem" "The Doctor's Daughter"

"The Poison Sky" is the fifth episode of the fourth series (since revival) of British science fiction television series Doctor Who. It was broadcast on BBC One on 3 May 2008. The episode features both former companion Martha Jones and the alien Sontarans. It is the second of a two-part story, following "The Sontaran Stratagem".

Plot

Synopsis

Immediately after the events of "The Sontaran Stratagem", the Doctor attempts to deactivate the ATMOS devices while Sylvia frees Wilfred from her car by smashing the windshield with an axe. The Doctor tells Donna's family to get inside and seal the windows and doors as best they can. He and Donna return to the ATMOS factory, where the Doctor warns UNIT not to engage the Sontarans. The Doctor tells Donna to stay in the TARDIS for her own safety, but the Sontarans locate and teleport the TARDIS aboard their ship. Meanwhile, the clone of Martha has given the Sontarans information and control over UNIT's computer systems.

The Doctor speaks to General Staal and learns that the Sontaran war with the Rutan Host is not going well, so the Sontarans need to convert Earth to a breeding planet where they can clone more troops. When the Sontarans prevent UNIT from launching a nuclear missile at their ship with help from the cloned Martha, the Doctor works out that since their ship was quite safe, the Sontarans were really preventing the disruption of their atmospheric conversion. UNIT attempt an attack on the ATMOS factory, but the Sontarans easily overwhelm their troops. UNIT manages a counterattack and calls in the aircraft carrier Valiant, which puts the Sontarans on the defensive. Finding the TARDIS missing, the Doctor sends Donna a coded message while speaking to General Staal and tells her to find and re-engage the teleport pods. Following UNIT's offensive, the Doctor ventures into the factory and discovers the real Martha in one of the Sontaran's cloning devices. Having long suspected the truth, the Doctor awakens the real Martha, killing the clone in the process. He tells Martha to keep UNIT from launching any missiles and rushes off.

The Doctor tells Donna how to use the teleport pods to return to Earth, and then uses the teleport to return the TARDIS to Earth. They teleport with Martha to Rattigan's institution, finding him distraught over the potential disaster to Earth that he caused. The Doctor collects the necessary equipment to construct his own atmospheric converter, which would harmlessly ignite the poison gas across the globe and end the threat. The poison gas burns off in the atmosphere and the Earth is saved. The Doctor is aware the Sontarans will not concede defeat but feels that he needs to give them a chance to withdraw. He teleports to the Sontaran ship and offers Staal the chance to retreat, but Staal calls the Doctor's bluff and encourages him to destroy them. Humbled, Rattigan reactivates the teleport and switches places with the Doctor, sacrificing himself to activate the device and destroy the Sontarans.

Afterward, Martha says goodbye to Donna and the Doctor inside the TARDIS and prepares to head home. Before she can leave however, the TARDIS doors suddenly snap shut and it dematerialises. Trapped on board, Martha is transported with the Doctor and Donna to an unknown destination, as the Doctor's severed hand begins to bubble in its jar under the console.

Continuity

Just as Donna moves towards the TARDIS screen while the Doctor contacts the Sontarans, Rose Tyler briefly appears on the screen, silently calling out. This follows a similarly silent appearance in "Partners in Crime". The Valiant, the primary setting for the climax of "The Sound of Drums" and much of "Last of the Time Lords", is seen again in this episode when it is used by UNIT to clear the poisonous gas from the atmosphere over the ATMOS factory. It is also equipped with a scaled-down version of the Torchwood weapon that destroyed the Sycorax ship in "The Christmas Invasion".

The Doctor remarks to Colonel Mace, "At times like this, I could do with the Brigadier...no offence." To which Colonel Mace responds, " None taken. Sir Alistair is a fine man, if not the best. Unfortunately, he's stranded in Peru." This is a reference to UNIT founder Brigadier Lethbridge-Stewart, who first appeared in the Season 5 serial The Web of Fear (1968). Radio callsigns for UNIT personnel remain "Grayhound" and "Trap" (each followed by numbers), just as they were during all of the UNIT stories during the Third Doctor's era. The Doctor jokingly asks Colonel Mace, "Are you my mummy?" while wearing a gas mask - a reference to a line spoken by gas mask-wearing characters in "The Empty Child" / "The Doctor Dances".

Production

This episode and the previous episode were filmed over five weeks, beginning in September 2007. Post-production was completed a week before the first part aired.

During production, director Douglas Mackinnon intended to have the episode's climactic scene in the TARDIS show the moveable column in the centre console move up and down much more rapidly than normal. However, when attempting to accomplish this, Mackinnon ended up breaking the prop, which took thirty minutes to repair.

When interviewed on Friday Night with Jonathan Ross, Catherine Tate stated that she had been filming alongside ten actors playing Sontarans for two weeks before she realised that there were actors inside the Sontaran costumes. She had assumed the Sontarans "ran on electricity". It was not until an actor removed his helmet to reveal his real face that she realised her mistake. She stated she was "freaked out" by this and said she "nearly died".

When the Doctor interrupts the Sontarans' transmission, animated footage from CBeebies's part live action, part animation eco adventure show Tommy Zoom is brought up on screen featuring the villainous Polluto disguised as a magician and the heroic Tommy and his dog Daniel as his audience. Originally, the plan was to use Shaun the Sheep, but this fell through.

As in many previous episodes of the revived series, supposed BBC News 24 footage is used featuring reports of unfolding events. However, as with the more recent appearances of such footage in Doctor Who, the channel is simply captioned on screen as 'News 24' devoid of the BBC logo. Since this episode was produced, the BBC News 24 channel was rebranded in real life as BBC News.

Donna's mispronunciation of Sontaran stems from the original production of The Time Warrior, the first Doctor Who serial to feature the Sontarans. Kevin Lindsay, who portrayed Linx in the story, pronounced the word as it has always been used, with emphasis on "Son-TAR-an", whereas the director Alan Bromly wanted it pronounced with no emphasis. Kevin Lindsay won the argument, claiming "I'm from the bloody planet, I think I know how to pronounce my own name!"

Scenes at the Rattigan Academy were filmed at Margam Country Park, Port Talbot.

Broadcast

Unofficial overnight figures indicated that "The Poison Sky" was watched by 5.9 million viewers, giving it a 32.5% share of the total television audience. The final consolidated figure was 6.53 million viewers. It was the second most watched programme of the day, being beaten by ITV's Britain's Got Talent, which got 9.12 million viewers. It was the highest rated programme on BBC1 for the day and the 18th most watched of the week. The episode received an Appreciation Index score of 88 (considered "Excellent").

External links

• The Poison Sky on TARDIS Data Core, an external wiki
• "The Poison Sky" at the BBC Doctor Who homepage
• "The Sontaran Stratagem" / "The Poison Sky" at Doctor Who: A Brief History of Time (Travel)
• "The Sontaran Stratagem" / "The Poison Sky" at the Doctor Who Reference Guide
• "The Poison Sky" at IMDb

Reviews

• "The Sontaran Stratagem" / "The Poison Sky" reviews at The Doctor Who Ratings Guide