The End of Time (TV story)

"Sometimes I think a Time Lord lives too long"

The End of Time is a two-part Doctor Who special that was broadcast during the 2009–2010 Christmas season, concluding the 2009 Specials "interim season." This was the last story for David Tennant as the Tenth Doctor prior to the character's regeneration into his eleventh incarnation, with Matt Smith making his first on screen appearance as the new Doctor. It is also the last Doctor Who story written by Russell T Davies. The two-part story is notable for revealing many aspects of the Last Great Time War.

Part 1
It is the Tenth Doctor's final journey - but his psychotic nemesis The Master has been reborn, on Christmas Eve. With both determined to cheat death, the battle ranges from the wastelands of London to the mysterious Immortality Gate, while the alien Ood warn of an even greater danger approaching, as a terrible shadow falls across the entire Universe.

Part 2
The Doctor faces the end of his life as the Master's plans hurtle out of control. With the sound of drums growing louder, and an ancient trap closing around the Earth, the Doctor and Wilf must fight alone. But sacrifices must be made, and the deadly prophecy warns: "He will knock four times."

Part 1
The Doctor arrives on the Ood Sphere, and sees that the Ood have progressed further technologically than they should have. Ood Sigma takes the Doctor to the Ood Elders who show him visions of the Master returning. He sees an old woman taking the Master's ring and he realises that the essence of the Master survived his death during their last encounter. The Doctor rushes to Earth in the TARDIS to try and find him. The scene shifts to Lucy Saxon, who has been incarcerated in Broadfell Prison ever since she murdered her husband. One of the warders of Broadfell is Miss Trefusis, the woman who retrieved the Master's ring. On Christmas Eve night, the prison governor brings Lucy to a chamber where it is revealed that most of the staff are fanatics of the Master who have been working ever since his apparent death to bring about his resurrection. With the help of the ring and a biometric imprint taken from Lucy, the Master reappears in a swirl of energy, but Lucy and some other warders have prepared for this eventuality and Lucy hurls a harmful potion at the Master. The Doctor arrives to find the prison obliterated by the resulting explosion.

The Master survives the blast, but his life force is left in a state of constant depletion, forcing him to drain the vitality of a number of homeless people on a desolate construction site. Like the Ood and many others on Earth, Wilfred Mott has experienced faded dreams of the Master, and has been scouring London with other pensioners, under the group name the "Silver Cloak", to track down the Doctor. Wilf and the Doctor re-unite and the Doctor reveals that a prophecy has been made predicting his death. Later encountering the Master, the Doctor discovers that the drumming in his head is not a symptom of insanity, but perfectly real. A squad of troops suddenly appear, sedating and kidnapping the Master and taking him to the mansion of billionaire Joshua Naismith. Naismith and his daughter, Abigail, are in possession of the "Immortality Gate", which has restorative powers enabling the healing of injuries and, as Naismith hopes, the resurrection of the dead. Wanting to secure immortality for Abigail, Naismith enlists the assistance of the Master to mend the malfunctioning Gate. Infiltrating the Naismith estate, the Doctor and Wilf discover that two of Naismith's staff are undercover Vinvocci, members of the race which originally owned the Gate, and that its healing abilities can extend to the whole population of any given species across a whole planet. She and her partner are pressured into explaining the Immortality Gate is a device that heals lifeforms across entire planets. The Doctor realises the Master is going to cause harm to the Human race and goes to stop him. He gets to the immortality gate but is captured. After the Master breaks out of his straight jacket and flies into the gateway then because he has set the gateway to Human and he is in the the machine every Human on Earth then becomes copies of the Master with the exception of Wilf who is shielded in the control room and Donna, who due to the last time she travelled with the Doctor is half human - half Time Lord. However as Donna witnesses her mother and her fiancée turn into clones of the Master she starts to remember everything that was erased from her memory. As the Master steps out of the gateway he tells the Doctor that he has turned the Humans into "The Master Race" as he looks round and everyone is the Master.

The Narrator claims the Master and his removal of Humanity is only a small part of an approaching conflict. The Narrator is revealed as a Time Lord he is addresses a large hall of fellow Time Lords and Time Ladies, who shout, "For Gallifrey! For victory! For the end of time itself!"

Part 2
The concluding part starts on a devastated Gallifrey, on the last day of the Time War. The Time Lord Council has foreseen that the Doctor, in possession of something called "The Moment", will end the war by destroying both Daleks and Gallifrey. The Time Lord President is adamant that he will not allow himself or his race to die. To try and prevent this, the Time Lord Council concocts a plan which involves retrospectively implanting a link to the Master during his early childhood (the four-beat drum rhythm that has tormented the Master all his life), followed by sending a Gallifreyan "Whitepoint Star" diamond to Earth as a further, more physical, link. This link to the Master's present location will then enable the Time Lords to escape from the Time War's Time Lock, and so escape their impending destruction at the hands of the Doctor.

On Earth, the Master threatens to kill Wilfred if the Doctor will not show him the TARDIS. The pair are saved by the Vinvocci. However, Rossiter, unable to free The Doctor from the chair he is strapped to, is forced to wheel the chair along, down several flights of stairs, prompting the Doctor to say 'worst...rescue...ever'! Reaching the basement, the group teleport to the orbiting Vinvocci ship, the Doctor destroying the ship's systems to prevent their detection. The Master broadcasts a message that he has found the Gallifreyan diamond, and that it can only mean the Time Lords are returning. The Doctor, having repaired the ship, returns to Naismith's mansion, to find he is too late. The Master is there, and so are the Time Lord Council. The action of the machine is reversed, restoring all humans and leaving only the original Master standing. Gallifrey begins to materialise near Earth, fulfilling the prophecy that "it" (a previously unspecified entity) is returning. The Master reveals he had planned to replicate himself into Time Lord bodies too, but is told by the Doctor that many other terrible things were sealed in the Time Lock as well – the reason for the destruction – and these are all returning too.

The Time Lord President reveals they had planned this moment since the Time War, that all creation and all of time will be destroyed and the Time Lords will become pure consciousness. The Master begins to realise that the Time Lords had planned to use his life as a means for them to escape their inevitable death, at the cost of creation itself.

After agonizing over who to shoot – the Master, or the Lord President (revealed moments later as Rassilon, founder of Time Lord society) – the Doctor finally targets the diamond which is anchoring the Time Lords outside the time lock, and the Master in return uses his superhuman powers to blast the Lord President back into the Time War. There is a bright flash of light, and the Time Lords, the Master (as he used up the last of his life force), and (somewhat slower) Gallifrey, are gone.

The Doctor struggles to his feet, not quite able to believe he has survived. Then in the moment he finally feels safe, he hears four hesitant knocks, the sound that portends his death. Wilfred is trapped in a radiation containment device and wants to be let out and can only be released at the cost of the Doctor's own life; fulfilling the prophecy that "he" (an unspecified person) will knock four times and the Doctor will die. After debating with himself as to whether he is willing to sacrifice his own life for Wilf's, he concludes he may have lived too long, releases Wilfred, and receives a massive level of radiation poisoning.

Although he survives initially, the effects on his body show that his regeneration has started. He takes Wilfred home and brief scenes show him helping his past companions in turn, including Donna who becomes married to her fiance, the final scene showing him staggering back to the TARDIS. As he collapses Ood Sigma appears to him, to tell him that the entire Universe would sing for him. Pushed on by this, he reaches the TARDIS, which he sets in motion, before his regeneration into the eleventh Doctor occurs in an unusually violent manner, shattering the TARDIS windows and setting the interior on fire. After the new Doctor remarks on his new body, he gleefully clings to the controls of the TARDIS as it plummets towards the Earth.

Cast

 * Tenth Doctor - David Tennant
 * Eleventh Doctor - Matt Smith
 * Wilfred Mott - Bernard Cribbins
 * The Master / The Master Race - John Simm
 * Rassilon - Timothy Dalton
 * The Woman - Claire Bloom
 * Donna Noble - Catherine Tate
 * Sylvia Noble - Jacqueline King
 * Shaun Temple - Karl Collins
 * Addams- Sinead Keenan
 * Rossiter- Lawry Lewin
 * Joshua Naismith - David Harewood
 * Abigail Naismith - Tracy Ifeachor
 * Σ|Ood Sigma - Paul Kasey
 * Ood Elder - Ruari Mears
 * Lucy Saxon - Alexandra Moen
 * The Visionary - Brid Brennan
 * The Second - Joe Dixon
 * The Partisan - Julie Legrand
 * Minnie Hooper - June Whitfield
 * Martha Smith-Jones - Freema Agyeman
 * Mickey Smith - Noel Clarke
 * Sarah Jane Smith - Elizabeth Sladen
 * Luke Smith - Tommy Knight
 * Jack Harkness - John Barrowman
 * Verity Newman - Jessica Hynes
 * Rose Tyler - Billie Piper
 * Jackie Tyler - Camille Coduri
 * Alonso Frame - Russell Tovey
 * Oliver Barnes - Barry Howard
 * Time Lord - Roger Bailey
 * Miss Trefusis - Sylvia Seymour
 * Governor - Teresa Banham
 * Mr Danes - Simon Thomas
 * Ood Voices - Silas Carson
 * Voice of Ood Elder - Brian Cox
 * Voice of Judoon - Nicholas Briggs
 * Trinity Wells - Lachele Carl
 * Nerys - Krystal Archer
 * Sarah - Lacey Bond
 * Tommo -Pete Lee-Wilson
 * Ginger - Max Benjamin
 * Graske - Jimmy Vee
 * Sontaran - Dan Starkey
 * Winston Katusi - Allister Bain
 * Neighbour - Jeanie Gold

Crew
to be added

Story Notes

 * This was David Tennant's last appearance as the Doctor and also Matt Smith's first appearance.
 * The second part is 75 minutes, four minutes longer than DW: Voyage of the Damned. Thus it is the new holder of the title of third longest single episode, behind the 85 minute long DW: TV movie and the 90 minute long DW: The Five Doctors.
 * The person who knocks four times was Wilf.
 * With this, his final Doctor Who story, Davies will have written or co-written no less than ten consecutive episodes (this number counts two-parters as separate and also includes a mini-episode, but does not include Torchwood), an unprecedented accomplishment in the history of the franchise.
 * This is the first story of more than one episode since DW: Survival to have one overarching title. It is unknown if this is one-off or will be continued under Steven Moffat.
 * The Time Lords return after their apparent destruction in the Last Great Time War. This is their first appearance onscreen since DW: The Trial of a Time Lord nearly 20 years eariler, except for a flashback in DW: The Sound of Drums.
 * This is, along with DW: The Deadly Assassin, Doctor Who, Army of Ghosts, and Human Nature one of the only Doctor Who stories to feature narration. However, in this case it is revealed that the "narration" is in fact part of a speech given by the Lord President to the High Council.
 * There is no traditional celebrity cameo in the story. Instead, a stand-in plays US President Barack Obama and stock audio from a speech of his is dubbed in. This is the first time in the revived series that the real-world US presidency has coincided with that featured in the Whoniverse.
 * The opening credits list David Tennant, John Simm and Bernard Cribbins. Simm is the second person to be credited in the opening credits for playing a villain. (The first was Eric Roberts, who likewise played the Master, in DW: TV Movie.) This is only the second time that all of the credits were male (the first being DW: The Next Doctor).
 * Despite this being David Tennant's last regular Doctor Who story, he filmed scenes for SJA:The Wedding of Sarah Jane Smith, after the production of this story.
 * In the Doctor Who Confidential for this episode, the TARDIS in the opening titles bears the St. Johns Ambulance badge, a nod to the Eleventh Doctor.
 * The continuity announcement before part 2 was voiced by the Tenth Doctor, and was the last time the Christmas ident featuring him was used.
 * Russell T Davies confirmed in the commentary for part 2 that the scene where Captain Jack is in an alien bar is in a city named Zagizalgul in the planet Zog. The scene, a tribute to the famous Cantina Bar scene in Star Wars Episode IV: A New Hope features cameo appearances by many alien species featured during the Davies era, plus the return of Alonso Frame (DW: Voyage of the Damned) and also features the song "My Angel Put the Devil in Me", last heard in DW: Daleks in Manhattan.
 * Russell T Davies has said in an interview that The Tenth Doctor's death had been planned out since David Tennant was signed on for the role. Davies also heavily implied had Tennant not been cast, the Tenth Doctor would have died a different way.
 * During the Doctor Who Confidential episode for part two, Davies stated that the name of the Vinvocci's ship was The Hesperus.
 * The Master redeems himself by sacrificing himself and saving the Doctor. According to historical accounts of the production of the classic series, this idea dates back to the original concept for Jon Pertwee's final story as the Third Doctor, which would have seen Roger Delgado's Master redeem himself in a similar fashion; Delgado's death ended this idea.
 * The scene with Luke Smith nearly getting hit by the car, was an in-joke regarding according to RTD, which is that none of the child actors look when crossing the road.
 * Given that the canoncity of the interactive of DW: Attack of the Graske and the fourth wall-breaking skit DW: Music of the Spheres are up for debate, the appearance of a Graske in the cantina scene marks the species' first undeniably canonical on-screen appearance in Doctor Who proper following several appearances in the spin-off The Sarah Jane Adventures.

Ratings

 * Part 1 - 11.57 Million - According to BARB.
 * Part 2 - 10.4 Million - According to unofficial overnight figures.


 * In America, three broadcasts of Part 2 garnered a combined total of 1.42 million viewers, a record for BBC America.

Filming Locations
to be added

Rumours

 * It was rumoured that Martha Jones and Mickey Smith would not appear (in particular given Freema Agyeman's commitments to the non-BBC production Law & Order: UK), however this was proved false as the two appeared as did Billie Piper and John Barrowman, whose involvement had been reported in the press during production of the specials.
 * Prior to the BBC's official announcement in mid-November, it was unclear whether Part 1 and Part 2 would both carry the same title (as prior to this only the title of Part 2 had been confirmed by the network). Following the broadcast of DW: The Waters of Mars, Russell T. Davies was quoted in the media as saying the title of Part 1 would have six words, leading to speculation over what it might be before it was announced that the two chapters would share the title The End of Time. The original name for the first part was "The Final Days of Planet Earth" but this was changed by Davies as he felt that it didn't fit the episode as a title.
 * It was hinted by Russell T. Davies that Donna Noble and/or Wilfred Mott would die, mentioning "Donna's final words" and speaking grimly of Wilf's fate in The End of Time. In another interview, Bernard Cribbins also made a cryptic statement regarding Wilf possibly "regenerating". Ultimately, both characters survived.
 * It was rumoured that Harriet Jones would re-appear, but she did not.
 * It was widely reported in media and on fan discussion boards that the character played by Claire Bloom would be the Doctor's mother. Ultimately, the woman's identity was left a mystery. Some people suppose it to be the Doctor's mother, others believe it to be an alternative world's Donna the way the Doctor looked at her after Wilf asked who the woman was, or, by the same logic, Susan, who is the Doctor's own granddaughter. Davies and Julie Gardner, in the episode commentary, stated that this woman is the Doctor's mother, however as this has yet to be indicated on screen or in spin-off media, it remains to be seen if this actually turns out to be the case.
 * Similarly, the identity of the other dissenting Time Lord is also left a mystery. The character is mentioned as male by Russell T. Davies, but the costuming and camera angles make it difficult to determine gender.
 * The Tenth Doctor's last words would be "Don't forget me". This stemmed from "A Letter from the Doctor", a feature written by Russell T. Davies for Doctor Who Storybook 2010 which consisted of fragments of dialogue and descriptions taken from TV various TV episodes, in reverse chronological order. The first words of the Letter are "Don't forget me", while the last were "Hello! Ooh, new teeth..." which were the first words uttered by the Tenth Doctor in DW: The Parting of the Ways. This led to newsgroup-based speculation that extrapolating from the format that the final words of the Tenth Doctor would be "Don't forget me." Ultimately, the final words of the Tenth Doctor were, instead, "I don't want to go." The Tenth Doctor does, however, say "Don't forget me." to Sarah Jane Smith when they part company in The Wedding of Sarah Jane Smith.

Discontinuity, Plot Holes, Errors

 * When the Master is restored to life, it is with a growth of facial hair, which he did not have prior to his death. (He had stubble when he regenerated into the Harold Saxon version of the Master, so arguably he is simply returning to the "default state" of this regeneration.)


 * If Lucy has been in prison for approx 2 years, how could the Master's DNA still be on her lips? (It's demonstrated in DW: Smith and Jones that a quick kiss is enough for a genetic transfer. Presumably, since the Master kissed Lucy many times, the genetic transfer lasted long enough for it to be cultivated at a later date.)


 * He also has blonde hair. (Episode commentary said he dyed his hair blonde in order to make himself look less like "Harold Saxon".)


 * Both Lucy's voice and personality seem dramatically different. (Since Lucy has been in jail she has had time to think about her actions with the Master, and has seen how evil he was. Arguably, the first inklings of this "new" personality occur as far back as DW: Last of the Time Lords when she shoots and kills the Master, with the implication he had abused her during the lost year.)


 * How does the sight of the Master make Donna remember? She has never met him before. (In DW: Journey's End, Donna gained all of the Doctor's memories and knowledge. She is thus well acquainted with the Master despite never having met him in person before.)


 * When talking about their previous encounters, Wilf mentions his paintgun although the Doctor wasn't there when he shot the Dalek. (It's possible that Wilf informed the Doctor of his encounter with the Dalek while they were waiting for Donna to awake in DW: Journey's End.)


 * It is said that Martha is married to Mickey but isn't she supposed to be married to Tom Milligan? (It is stated previously that Martha is married, but never to whom. Her relationship with Milligan obviously ended, and she married Mickey.)


 * How did the Doctor know where Captain Jack Harkness was? Since the Doctor was able to track down Naismith earlier through the TARDIS, he probably did the same here.


 * Why did the TARDIS explode during the regeneration scene? This hasn't happened before. (Regeneration is unpredictable, and some are more violent than others. This one actually began right after he saved Wilf, however, the Doctor fought it long enough to visit each of his companions one more time. It is possible that holding back the regeneration for so long caused a more violent reaction when it finally did happen.)


 * Why did the Doctor choose to meet Verity Newman, a descendant of Joan Redfern, and not Redfern herself? The Doctor has already caused Redfern a great deal of heartache and he likely does not wish to reopen old wounds.


 * It was stated in the "Meet the Doctor" section of Doctor Who Annual 2006 that the President of the Time Lords during the Time War was Romana - Rassilon is not mentioned. In the narration by Rassilon at the end of Part 1, he states that the Master's actions had a wider consequence .


 * If the Doctor saw Rose from 2005, Wouldn't that create a paradox due to the fact Rose has not met the Doctor yet? (The Doctor stayed in the shadows at the end, not wanting Rose to see his face. She asked if he had been drinking, so she would have dismissed him as a drunk and likely not remembered him from the incident.)


 * What was accelerating the Ood's evolution? The Ood Elder stated that "Time is bleeding", presumably, this affected certain points in time, including the Ood's evolution cycle. 


 * As Rossiter is climbing into the mining laser pod while the Vinvocci ship is under fire from the missiles, his face is the colour of human skin, instead of the traditional Vinvocci green. The green coloring on the Vinvocci skin was enhanced in post-production. They simply missed a sequence.


 * The room with The Gate was shaking because of Gallifrey coming closer, but then it stopped shaking when the Doctor picked up the gun. Why was this? A directorial issue, to emphasise the importance of the Doctor picking up the gun.


 * Rassilon's personality is nothing like it was in the DW: The Five Doctors, and since when is he evil? Rassilon has always been portrayed as an ambiguous character at best. Although not necessarily evil, there has been previous reference made that Rassilon had a dark component to his persona. For example, the Doctor said in DW: Five Doctors that it was rumored, contrary to the official story of Rassilon's "death", he was deposed when the council rebelled against his cruelty.


 * Why is a piece of music from 1930's Earth playing in a space cantina? Some aliens are interested in Earth culture.


 * In DW: Smith and Jones, the Doctor clearly states that he can expel radiation from his body if he focuses hard enough, so therefore why does he need to regenerate? (The damage has been done. There is a misconception that all radiation is the same, in reality there are several types and as shown in several stories (DW: The Daleks, The Mutants, Planet of the Spiders etc) it is shown that Alpha and Beta particle radiation is lethal to Time Lords (to a lower extent) while what's in the electromagnetic spectrum is near harmless to them (i.e Gamma rays, Ultra Violet, X-rays etc.). Furthermore, the Doctor was already in a weakened state after surviving the fall from the mining ship.)


 * When Wilfred is trapped in the radiation chamber, why couldn't the Doctor leave and come back with a teleportation device, some other means to repair the chamber, or even a radiation suit of some kind? Perhaps even replicate the TARDIS effect he used in DW: The Doctor Dances to rescue Jack Harkness from his exploding ship? (By the time the Doctor did any of those things, Wilf would have died, and the Doctor has accepted the fact that he has to save Wilf at the cost of his own life.)


 * How did the Doctor survive jumping out of a moving spaceship, crashing through the skylight, and landing on the marble floor? A lesser fall onto grass killed the Fourth Doctor. Physically each Doctor is different and can be expected to be more or less durable than the others. In addition, the Tenth Doctor mentions he can survive a fall of at least thirty feet in the episode DW: The Satan Pit


 * When the Doctor decides whether to shoot the Master or the President he holds the gun in different hands (left when pointing at the Master right when pointing at Rassilon) (You can see him change hands.)


 * When the Doctor is aiming the gun at both the Master and Rassilon, you can see (and hear) that he has quite obviously pulled the trigger on each occasion. The Doctor is holding the trigger close to the point of shooting a bullet: as he changes targets, he changes hands where he is holding the trigger closely to the point of firing each time. 


 * If Rassilon's glove is so powerful why would he hesitate to use it when the Doctor points a mere revolver at him? (Even if he did fire, the Doctor would have time to fire as well.)


 * The security camera footage viewed by Joshua Naismith on his laptop is the same as the footage used in the episode DW: Rose on the news bulletin showing the destruction of the Henrik's Department Store.


 * After the Doctor hits the Sontaran the scene cuts from a close-up shot to a full-body shot. However, no Sontaran is visible in the full-body shot.


 * Wilfred states that the Doctor mentioned regeneration to him during a previous encounter, although no such scene appears in previous episodes. Given that the Doctor doesn't mention the subject in casual conversation (Rose, Donna and Martha were never made aware of it until the possibility of it happening appeared), this seems unusual. Also, it seems unclear when the Doctor would have had occasion or reason to mention regeneration to Wilfred.In DW: Journey's End he explained the Meta-Crisis to Wilf and Sylvia offscreen.


 * Why weren't Earth and Gallifrey both ripped apart immediately by gravitational forces when the latter materialised in such close proximity? Gallifrey hadn't completely materialised yet, so it hadn't become solid enough for it's mass to completely destroy the Earth.
 * How does The Woman manage to contact Wilf by appearing in his television, let alone in person, when the other Time Lords have difficulties sending a signal through to The Master? Because she is no ordinary Time Lady, there is something about her that no one quite understands. One theory suggests that when she appears to Wilf in white, she is dead, and that version of The Woman is her further on her personal timeline. 
 * Why are the two Time Lords that disagreed with Rassilons decision taken along to Earth? Taking them to Earth seems to serve no purpose.
 * Rassilon is the Time Lord who helped make Time Lords what they are. He was meant to be in eternal sleep, so how did he return?

International broadcasts

 * United States: BBC America aired Part 1 on 26 December 2009, followed by Part 2 on 2 January 2010, only a day after the UK broadcast.
 * Canada: Space aired both parts back-to-back on 2 January 2010 as part of a daylong Doctor Who/Torchwood marathon. It was also rebroadcast on 3 January.
 * Australia: ABC1 is scheduled to air Part 1 on 14 February 2010, and Part 2 on 21 February 2010.
 * New Zealand and other countries: TBA

Continuity

 * The fall of Torchwood is mentioned (DW: Army of Ghosts / Doomsday) and/or (TW: Children of Earth)
 * The Master returns, and there is flashbacks to the events of DW: Last of the Time Lords, which briefly include Martha Jones, Francine Jones, and Captain Jack Harkness.
 * The Immortality Gate was previously referenced in SJA: The Wedding of Sarah Jane Smith, as "the Gate"
 * When Donna remembers the Doctor several things from her time with him appear, included are Empress of the Racnoss, (DW: The Runaway Bride), the Adipose (DW: Partners in Crime), Ood (DW: Planet of the Ood), the Suit Creature (DW: Silence in the Library/ Forest of the Dead), the Vespiform (DW: The Unicorn and the Wasp), Sontarans (DW: The Sontaran Stratagem/ The Poison Sky), a Pyrovile (DW: The Fires of Pompeii), Dalek Caan, Davros and the Supreme Dalek. (DW: The Stolen Earth / Journey's End) The Judoon (DW: The Stolen Earth) can also be heard in her memories.
 * Alonso Frame (DW: Voyage of the Damned) is sitting next to Jack, who appears depressed, in an alien bar, and the Doctor hints they should start a realtionship, following his loss of Ianto Jones. (TW: Children of Earth)
 * The Doctor mentions Joan Redfern to her granddaughter Verity, asking if she was happy after "John Smith" had gone, referencing the events of DW: Human Nature/ The Family of Blood.
 * The song My Angel Put the Devil in Me first heard in DW: Daleks in Manhattan.
 * The circumstances of the Tenth Doctor's regeneration echo that of the Ninth: Absorbing a massive amount of energy into his body, in order to save the life of another. (DW: Parting of the Ways)
 * The Doctor previously suffered near-lethal radiation poisoning DW: Planet of the Spiders
 * Donna's neighbour who appeared throughout Series 4 is finally given a name in part one, Sally.
 * Nerys previously appeared in DW: The Runaway Bride.
 * The notion of Gallifrey being moved due to Time Lord action from the constellation of Kasterborous to Earth's solar system isn't the first time the Time Lords have shown the ability to relocate an entire planet. In DW: The Mysterious Planet, the planet Ravalox is revealed to be Earth, relocated to another part of the universe by the Time Lords. And DW: Journey's End revealed that (with a little assist), a single TARDIS is powerful enough to move the Earth.
 * The Doctor knocks out a Sontaran using the exact same method used by Donna in DW: The Poison Sky
 * The Doctor states that he is 906 years old, implying that three years had past in his personal timeline between DW: Voyage of the Damned and this episode.

'Ginger' controversy
During the final scene, the Eleventh Doctor takes a look at his hair and utters the phrase, "Still not ginger!". This statement was misinterpreted by a number of viewers as being a negative comment on redheaded people, resulting in more than 140 complaints being filed with the BBC. In response, the BBC issued an official statement clarifying that the Doctor was stating disappointment at not being ginger, a reference to the Tenth Doctor similarly expressing a wish to be ginger in DW: The Christmas Invasion. In response to claims of an "anti-ginger agenda" by the series, the BBC statement noted that the Doctor's two most recent ongoing companions, Donna Noble and the yet-to-be-introduced Amy Pond, are both redheads.

DVD Release

 * It has been announced that the four specials plus The Next Doctor will be released in North America on both DVD and Blu-Ray in a box set on 2nd February 2010.