New Earth (TV story)

New Earth was the first episode of series 2 of Doctor Who.

It served as the middle of a loose "New Earth" trilogy, incorporating The End of the World and Gridlock. It featured reappearances of Cassandra O'Brien.Δ17 and the Face of Boe, both last seen in End of the World, and introduced a mystery surrounding the Face of Boe that would later be a major part of the overall story arc of series three. It was also the first BBC Wales episode to be set on an alien world (with the exception of a brief beginning scene of Rose saying her goodbyes on Earth), the entirety of series one having taken place on or in orbit of Earth.

Behind the scenes, it was the final appearance of Zoë Wanamaker, but it was the first time that actors Anna Hope and Adjoa Andoh worked on the programme. Principal photography was rocky enough to be remarked upon by two different sets of commentators. Its overruns and difficulties negatively impacted upon other episodes within its production block. (PCOM, DCOM: New Earth)

Series two also played host to a series of mini-episode prologues for each new episode, known collectively as Tardisodes. Tardisode 1, the first of these short preludes, led into New Earth. A follow-up on Hope's character Novice Hame, The Secret of Novice Hame, was made for the Doctor Who: Lockdown! event.

Synopsis
In the distant future, an order of cat-nuns cure all illnesses, but the Tenth Doctor is suspicious of their methods. He must uncover the truth and save Rose from the vengeance of his old enemy, the Lady Cassandra.

Plot
The Tenth Doctor powers up the TARDIS as Rose says her goodbyes to Jackie and Mickey at the Powell Estate. Although Jackie and Mickey sadly watch the TARDIS fade away, inside the ship Rose is all smiles as she asks the Doctor where they are going next. He tells her that they are going further than they have ever gone before.

The TARDIS materialises on New Earth, in the year five billion and twenty-three. Following the destruction of Earth, humanity became nostalgic and settled on a new planet with similar gravity and atmosphere in Galaxy M87. Rose is delighted at the new world, the sight of the futuristic city of New New York in front of them and the smell of apple-grass. The Doctor points out that it's the fifteenth York since the original; so it's technically New New New New New New New New New New New New New New New York. Rose laughs that he's so different. "New New Doctor" he jokes back. However, the two travellers are unaware they are being observed by a metal spider remote-controlled by Chip, a small, pale man with multiple tattoos. Chip takes his orders from his mistress, Lady Cassandra, who is still alive and recognises Rose.

The Doctor and Rose head for the New New York Hospital, to which the Doctor has been summoned by a telepathic message displayed on his psychic paper: "Ward 26, Please Come". The luxurious facility is run by humanoid feline nuns belonging to an order called the Sisters of Plenitude; though Rose is a bit shocked, the Doctor tells her that the cats would find her equally strange due to her "pink and yellow" colouration. Trying to find the right ward, the Doctor and Rose enter separate lifts, which drench each of them in disinfectant liquid and powder before blowing them dry — the Doctor is completely blasé about it, while Rose, who had not been expecting the cleanse, takes a while to get used to it. Chip overrides Rose's lift controls, diverting her down to the basement. When she emerges, he beckons her forward, calling her by name. Suspicious, she grabs a metal pipe as a weapon and follows him.

The Doctor is escorted through Ward 26 by Sister Jatt, commenting that the hospital lacks the little shop he is so fond of. Sister Jatt lectures him on the vow that her order takes, which is to help and mend, as they pass a bed belonging to an incredibly fat man who appears to be turning to stone. The rather severe woman at his bedside, Frau Clovis, rebukes the Doctor for staring at the man, who is the Duke of Manhattan and is dying from Petrifold Regression. Sister Jatt is confident that the Duke will be healed in no time, despite the fact that the cure for his disease won't be available for another thousand years, and asks the Doctor if he recognises any of the patients. The Doctor, with a smile on his face, responds that he does — his mysterious summoner is none other than the Face of Boe. He is being tended to by Novice Hame, who tells the Doctor that the Face is dying of old age — the one thing the Sisters can't cure.

Rose explores the basement warily and finds a film depicting a glamorous party with several men and a blonde woman whose familiar voice makes her turn to see Cassandra: a piece of skin stretched out on a frame over a brain jar. The self-proclaimed "Last Human" has reconstructed herself using another piece of her skin, and Chip — a force-grown clone devoted to Cassandra — smuggled her into the hospital, where he has been tending to her ever since. Cassandra has suspicions that the Sisters are hiding something, and she needs Rose's help... or rather, her body. Using a device called a psychograft, Cassandra's consciousness is transferred into Rose's mind, taking control of her body and leaving her old one to die. Cassandra is initially unimpressed with her new body — protesting, "I'm a chav!" upon seeing her reflection in a mirror — but changes her mind after taking a good look at Rose's curves.

In Ward 26, Novice Hame tells the Doctor of the legends surrounding the Face of Boe, who is said to have lived for thousands, perhaps millions of years and will give his dying message to a wanderer without a home, a "Lonely God". The Doctor realises that he fits the description in the legend, but says nothing. Below, Cassandra reads Rose's surface thoughts and discovers that the man with Rose is the Doctor with a new face. Believing he can help her discover the Sisterhood's secrets, she goes to meet him after hiding a tiny perfume spray in her cleavage.

Upstairs, the Doctor is astonished to discover the Duke of Manhattan in perfect health and interrogates one of the nurses, who introduces herself as Matron Casp, on how they were able to cure him, but she evades his questions and is summoned to the Intensive Care ward by Sister Jatt. There, they observe an unseen "patient" who pleads for help and are amazed that it can speak, before Casp orders it incinerated.

Cassandra joins the Doctor in Ward 26, and he promptly explains his confusion to "Rose"; there are various vaccines for several incurable diseases, including Marconi's Disease, which leaves the victim with bright red skin and should take years to recover from, and Pallidome Pancrosis which should kill the victim within ten minutes. Cassandra's odd behaviour in Rose's body — at one point even giving the Doctor a lusty kiss — raises the Time Lord's suspicions; though with regards to the kiss, he dizzily states "Yep. Still got it."

Through a secret terminal, the Doctor and Cassandra enter Intensive Care, where they discover the horrifying secret of the cures: hundreds of pods, each holding an artificially-grown human being infected with a thousand different diseases. The Sisters have built a human farm to breed cures, and kill any healthy enough to speak or move. The Doctor confronts Novice Hame, but she insists that these artificial humans are just "flesh", and that it was necessary to cope with the influx of patients and diseases that humanity brought to New Earth. The Doctor then demands the Sisters reverse what they have done to Rose, having noticed her lack of empathy but not realising that it is Cassandra who has taken over. Her cover blown, Cassandra reveals her identity to the Doctor and knocks him out with the drugged perfume hidden in her bosom.

While the Doctor is trapped in a pod about to be injected with diseases, Cassandra tries to blackmail Matron Casp, demanding money in exchange for her silence on the Sisters' actions. Casp declines and threatens her physically with her rather vicious claws. In response, Cassandra has Chip release some of the plague carriers to cover her escape. One sacrifices himself to trigger a power surge which releases the rest of the patients. The diseased carriers then advance on the nuns, trapping Sister Jatt, who screams in agony as one of them touches her face and infects her; the viruses are too numerous for her immune system to cope with and she is killed instantly. As the carriers spread throughout the building, Casp places the hospital under quarantine and the exits seal themselves, much to the confusion and fright of the staff and visitors.

Fleeing to the bowels of the hospital, Chip is separated from the Doctor and Cassandra by a group of carriers and Cassandra callously leaves him to his fate. Trapped in Cassandra's hiding place in the basement with the test-subjects mindlessly asking for help at the doors, the Doctor demands that Cassandra leave Rose's body; she complies, going into his body instead. Rose regains her senses, seeing Cassandra adapt to the Doctor's form; noting his two hearts and "hardly used" parts. She taunts Rose; having been in her head, she knows Rose finds the Doctor attractive. As the carriers breach the doors, Rose spots a ladder they can use to climb up an abandoned lift shaft and escape.

Rose climbs up the shaft with a now Cassandra-controlled Doctor, pursued by the carriers. Matron Casp tries to stop them, grabbing Rose's foot under the mistaken assumption she's Cassandra. However, before she can do anything else, one of the carriers touches her and the infected Matron falls screaming down the shaft to her death. As the Doctor is blocking his thoughts from Cassandra, she goes back into Rose so he can use the sonic screwdriver to open the door. The Doctor then demands Cassandra leave Rose, so she shifts her consciousness back to him again. Rose urges Cassandra to do something or they will both die. To her disgust, Cassandra transfers herself to a plague carrier so that the Doctor can finally use the sonic screwdriver to unseal the lift doors, then jumps back into Rose at the last moment. The Doctor is furious, but Cassandra is shocked by the loneliness of the carriers, having read the surface thoughts of the test-subject she had possessed — not being able to touch or be touched all their lives.

The Doctor and Cassandra reach Ward 26, which seems to be the only place still untouched by the carriers. Frau Clovis reveals a device she is using to try and contact New New York for help, but the Doctor refuses to allow it as every single disease in the galaxy is contained within the hospital and if the quarantine is breached then the whole planet will be at risk. He grabs all of the intravenous solutions, straps them to his body, then uses a winch to slide down the shaft with Cassandra to the lift car at the bottom, where he empties the solutions into the disinfectant reservoir. He opens the doors, luring several plague carriers inside as Cassandra starts the shower. The spray drenches the carriers, curing them, and the Doctor encourages them to pass it on; they wander back out to spread the cure to the others. A new race is born: the new humans, who Cassandra can no longer deny, as she herself helped create them.

As evening falls over New Earth, the surviving Sisters are arrested by the New New York Police Department, including Novice Hame, and the cured new humans are taken into care. The Doctor remembers the Face of Boe and returns with Cassandra to Ward 26. No longer dying, the Face tells him telepathically that he had grown tired of the universe, but the Doctor has taught him to look at it anew. The Doctor asks the Face about his message but is cryptically told it can wait for their third and final meeting. The Face then teleports himself away.

The Doctor orders Cassandra to leave Rose's body at once, telling her to end it. In response, Cassandra starts to sob and tells the Doctor she doesn't want to die. Chip then appears, having preserved himself from infection; he volunteers his own body as Cassandra's new vessel. Despite the Doctor's protests, Cassandra transfers her consciousness into Chip, freeing Rose at last. Unfortunately, her servant's "half-life" body quickly fails, and Cassandra accepts her impending true death; New Earth has no place for people like her and Chip anymore.

The Doctor does one last favour for Cassandra, taking her back to the party seen in the film earlier, to the last time anyone had called her beautiful, to re-witness her life as it was in its prime. "Chip" approaches the Cassandra of the past and sincerely remarks on her beauty, before collapsing into the younger Cassandra's arms as she comforts "him". As Cassandra finally dies, the Doctor and Rose silently leave in the TARDIS.

Cast

 * The Doctor — David Tennant
 * Rose Tyler — Billie Piper
 * Jackie Tyler — Camille Coduri
 * Mickey Smith — Noel Clarke
 * Cassandra - Zoe Wanamaker
 * Chip — Sean Gallagher
 * Matron Casp — Dona Croll
 * Duke of Manhattan — Michael Fitzgerald
 * Fran Clovis — Lucy Robinson
 * Sister Jatt — Adjoa Andoh
 * Novice Hame — Anna Hope
 * Patient — Simon Ludders
 * Face of Boe — Struan Rodger

Uncredited Cast

 * Butler - Stuart Ashman
 * Cat Nuns - Liza Meggitt, Hazel Beauchamp, Jade Kenning, Natalie Cuzner, Nia Collier

Individuals

 * The Ambassador of Thrace hosted a party Cassandra once attended.
 * Cassandra refers to herself as a chav while inside Rose's body.
 * The Duke of Manhattan has a butler.
 * The Doctor remarks how he dislikes hospitals but he likes their shops.
 * Rose mentions her cousin Mo from the Peak District when saying goodbye to Jackie.

Plants

 * Apple-grass is growing on the hillside where the TARDIS lands.

Diseases and illnesses

 * The Duke of Manhattan is suffering from Petrifold Regression.
 * Marconi's Disease, from which one of the patients suffers, takes years to recover.
 * Pallidome Pancrosis kills the sufferer within ten minutes.

Cultural references

 * Rose refers to Chip as Gollum.

Foods and beverages

 * The Duke of Manhattan offers the Doctor a glass of champagne.

Languages

 * Cassandra speaks some French.
 * At Chip's suggestion, Cassandra uses Cockney rhyming slang in an attempt to impersonate Rose.

Story notes

 * Working titles for the episode were Body Swap and The Sunshine Camp.
 * It is implied by the Doctor in The Runaway Bride that he stayed at the Powell Estate with Rose and Jackie between The Christmas Invasion and this episode.
 * This is the first story of the revived series to be set on an alien planet. Ironically, the first non-Earth planet the Doctor visits in the revived series is called New Earth (all on-camera locations up to that point were either Earth or space stations or spaceships in orbit around Earth).
 * This is the first Doctor Who episode to have an accompanying Tardisode. These short prelude scenes were made available online and via mobile phone a week prior to the broadcast. In the case of New Earth, the Tardisode consisted of a faux commercial advertising the Sisters of Plenitude's services.
 * Immediately after the episode, a commentary for the episode, featuring David Tennant, Russell T Davies and Phil Collinson, was made available on the official website for viewers to download and listen to alongside the repeat. The same thing was done for The Christmas Invasion.
 * According to David Tennant on the audio commentary, Billie Piper wore a Wonderbra and a slightly different shade of lipstick in the scenes where Cassandra was in Rose's body. He also mentioned that Billie kept on wearing the Wonderbra for a bit longer after Cassandra was no longer possessing Rose.
 * The words "bitch" and "arse" are implied, although not actually said. In both cases, the character (Cassandra and Rose, respectively) is cut off in their dialogue and the words are implied by the next word in the script. Cassandra, when talking of Rose, calls her "that little..." and then the scene cuts to Rose whose first words are "bit rich". Later, Rose tells Cassandra she is "talking out of [her]..." and Cassandra interrupts, "Ask not!"
 * When Cassandra takes over the Doctor's body she references to some parts that have been "hardly used", a reference to the perceived asexual nature of the Doctor. This may also refer to the fact that this is a newly regenerated body, and that he hasn't really had a chance to "use" most of the parts very much at this point.
 * The scene showing Rose kissing the Doctor was featured in one of the trailers and raised a stir in fan circles, despite the "kiss" shared by the Ninth Doctor and Rose in The Parting of the Ways. Ultimately, we learn it's actually Cassandra doing the kissing while possessing Rose. Rose and the Doctor never do kiss on screen in that fashion, though Rose will eventually kiss the Meta-Crisis Tenth Doctor in Journey's End.
 * This episode marks the first appearance of a running joke about the Tenth Doctor's love of the "little shops" found in hospitals and museums.
 * This episode marks the first use of the recurring phrase "I'm sorry, I'm so sorry" in the series.
 * The exterior shots of the lift car as Rose descends to the basement are stock footage recycled from Rose.
 * When the wall drops, the sound made is recycled from the movement of the Daleks.
 * Russell T Davies explains during the audio commentary that in the original script, the Face of Boe was going to die in this episode and the only way for the Doctor to cure all the diseased was to kill them all. But then he read Steven Moffat's introduction segment in The Shooting Scripts book, in which Moffat good-naturedly mocked Davies by stating he "creates interesting characters and then melts them". This made Davies decide to have them all survive instead.
 * Russell T Davies originally intended for the Face of Boe to tell the Doctor "You are not alone" in this episode. However when Billie Piper decided she would be leaving at the end of series 2 he opted to save this message and revelation for Gridlock, the following series.
 * This is the only series opener during Russell T Davies' tenure as showrunner to include a cold open.
 * The voice Billie Piper does for Cassandra is her natural accent.
 * Russell T Davies said of the episode "I promised Billie [Piper] an episode in which she'd be funny. So episode one of the new series is very much based around comedy for Billie."
 * Rose suddenly has her hair up at the end of the episode and wears a cap in the opening scene, to hide the fact that Billie Piper is still wearing her hair extensions from The Christmas Invasion.
 * Cassandra's face and body was put in during post-production by The Mill.
 * The producer's and director's credits have been amended slightly since The Christmas Invasion, so that now the credit is in lower case and the name of the crewmember is in capitals. This was the result of a suggestion from a Doctor Who Magazine editor, who felt the previous arrangement had made the job seem more important than the crewmember.
 * According to Russell T Davies on the episode commentary, Cassandra's earlier self bases Chip on the man who had praised her beauty at the party — Chip himself. Where the "pattern" for Chip comes from in the first instance is thus unclear, creating an ontological paradox.
 * Billie Piper didn't know she was going to be hit with water in the lift, Russell T Davies kept it in the final cut as he thought it was too funny to cut it.
 * Because production fell behind schedule, several scenes were dropped. Many of these concerned the Duke of Manhattan and Frau Clovis. Originally, they first appeared in the hospital foyer when the Doctor initially arrives; as scripted, the Doctor immediately earns the Sisters of Plenitude's disfavour when he saves the Duke's life. Later, Clovis mutinies when the Duke refuses to help defend the hospital against the Intensive Care patients. Another scene that would've been cut would've been a scene that bridged the gap between the Doctor and Rose leaving the hospital with Cassandra and arriving at the party where she dies in Chip's body. The missing scene would've had the Doctor making clear he hadn't forgotten the deaths Cassandra caused on Platform One during The End of the World and added more context to Cassandra's death scene.
 * A longer version of the scene where a Cassandra-possessed Rose rejoins the Doctor in Ward 26 originally had her meeting the Duke of Manhattan. As with the Doctor, the Duke's butler would have offered "Rose" a glass of champagne, prompting her to slip out of character and replying "Oh, moisturise me".
 * A brief scene involving the Face of Boe was cut immediately following on from the snog between Cassandra and the Doctor. It saw Novice Hame noticing the Face of Boe had opened his eyes and heading off to find the Doctor, thus explaining why she happens to walk in right as the Doctor and Cassandra pass through the secret entrance leading to Intensive Care.
 * Cassandra's servant was envisioned as a dwarf named Zaggit, but as the character's importance grew during the scripting process, he developed into Chip.
 * In the commentary, David Tennant noted that the TARDIS has moved since The Christmas Invasion. He speculates that there might have been many off-screen adventures, or (observing that it no longer seems like Christmas in the introduction) perhaps that the Doctor "lived there for a bit".
 * Netflix DVD copies of this episode were pulled in January 2007 after footage from The Texas Chainsaw Massacre: The Beginning was spliced into the DVD by accident.
 * Zoe Wanamaker had thoroughly enjoyed her involvement with The End of the World, but she was already committed to the Poirot episode "Cards on the Table", during the planned recording dates. Russell T Davies contemplated the possibility of reimagining the villain of the piece to be Cassandra's heretofore unrevealed sister Roseanne, who could be played by a different actress. Fortunately, however, arrangements were made for Wanamaker to film the party scene more than a month ahead of the majority of the episode.
 * Cassandra's 'stretched skin' appearances were kept to a minimum because these scenes were gruelling to computer-animate.
 * The episode originally took place on the plant Coffra.
 * The Sisters of Plentitude were originally called the Sisters of Patience.
 * The medical facility was called the Hospital of Evergreen Days at one stage.
 * Filming was interrupted when Billie Piper's then-boyfriend, Amadu Sowe, inadvertently damaged the Face of Boe prop, necessitating hasty repairs.
 * Filming was briefly delayed when Billie Piper became ill.
 * Filming at the Gower Peninsula was hampered by driving wind and rain, and insufficient daylight forced the abandonment of the last scene to be recorded. Intended to bridge the final hospital sequence and the material at Cassandra's party, it was replaced by a voiceover from the Doctor. It was belatedly discovered that a camera had malfunctioned during the shoot, resulting in the loss of various close-ups.
 * Although the episode had been designed to serve as the season premiere, Russell T Davies reconsidered its position in the schedule more than once. Before production began, he had suggested that it might swap places with The Girl in the Fireplace which, at that stage, was intended to be the second story in the broadcast order. Closer to transmission, there was discussion about running Tooth and Claw first and then New Earth second; the latter's fraught production had provoked some concern that it didn't represent the series at its best, and might discourage an audience which was still becoming accustomed to the Tenth Doctor. Indeed, the opening scene involving the Doctor and Rose had been written and recorded such that it could easily be appended to the start of a different episode, if need be. In the end, however, it was agreed that New Earth was naturally suited for the pole position, while Jane Tranter felt that its relatively light-hearted narrative was a more appropriate season premiere than the atmospheric Tooth and Claw.
 * Not long before the transmission, Phil Collinson requested changes to some of the computer-generated effects involving the hospital exterior. Previously, the facility had been depicted as being isolated, but Collinson thought that the absence of other buildings looked unnatural. Additional structures and new architectural detail were hastily added to the images in response to his criticisms.

Ratings

 * 8.62 million viewers (UK final)

Filming locations

 * The exterior shots of New Earth were filmed on the Gower Peninsula.
 * The hospital foyer scenes were filmed inside the Wales Millennium Centre which appeared in the previous series episode Boom Town. When the Doctor asks about the shop and points to where he would put it, he points to the location of the centre's own Portmeirion shop (so-called because it sells the unique Portmeirion china produced in the Welsh resort village of the same name that was once used as a filming location for The Masque of Mandragora).
 * The scenes taking place inside Cassandra's basement lair were filmed in the cellar of Tredegar House in Newport. The location was previously used for Harriet Jones's televised speech in The Christmas Invasion.
 * The location for the pods containing the human specimens was the disused (and since-demolished) Ely Paper Mill in Grangetown, Cardiff, which was previously used as the base of the Nestene Consciousness in Rose.
 * The drinks party the Doctor and Rose take Cassandra (as Chip) to at the end was filmed at the Ba Orient dim-sum restaurant on Mermaid Quay in Cardiff Bay. As the sequence was filmed during the day, the building was covered with black drapes to simulate night-time.
 * One of the New New York hospital buildings uses a slightly edited image of the Burj al Arab hotel in Dubai.

Production errors

 * When the camera zooms out when Rose is captured and Cassandra is about to "go" into Rose, the psychograft VFX disappears, but in the next shot of Rose, it is there again.
 * Before the Doctor and Rose/Cassandra open one of the booths, behind the Doctor there is an empty booth. In the next shot, there is clearly one of the Flesh occupying it.
 * At 5.30 Rose enters the right-hand lift but at 6.20 she leaves the left hand one.
 * Despte being soaked, powdered and blow-dried during the disinfection process, Rose's mascara remains unsmudged.
 * Rose/Cassandra removes Rose's blue jacket off-screen to better show off her new body, but when she later returns to the basement with the Doctor, the jacket is nowhere to be seen.

Continuity

 * There have been several planets called New Earth:
 * The planet, which turned out to be fake, to which Sarah was told she was being taken in a spaceship (TV: Invasion of the Dinosaurs)
 * A planet invaded by the Daleks (COMIC: Doctor Who and the Dogs of Doom)
 * The homeworld of the Sixth Doctor's companion Grant Markham (PROSE: Time of Your Life)
 * The New Earth Republic, a future Earth colony. (PROSE: Synthespians™)
 * The Seventh Doctor previously encountered another race of feline humanoids, the Cheetah People. (TV: Survival) The Second Doctor also met a feline race called the Cat-People. (PROSE: Invasion of the Cat-People)
 * The Doctor remarks how he does not like hospitals, given his previous experience in one. (TV: Doctor Who)
 * The ailment from which the Duke of Manhattan is dying, Petrifold Regression (a disease that turns its victims to stone), is also mentioned in PROSE: The Stone Rose. In TV: The Time of Angels, Amy Pond thinks she's suffering from a similar condition caused by the Weeping Angels.
 * The Bad Wolf car park graffiti is present, though faded when Rose is saying her goodbyes. (TV: The Parting of the Ways)
 * Cassandra references her last encounter with the Doctor and Rose, during which she was thought to have died. (TV: The End of the World)
 * Rose and the Doctor recall their "first date" and how they had chips. (TV: The End of the World)
 * Cassandra believes it to be hypocritical that the "same Doctor" she met on Platform One has a "new face", believing him to have undergone plastic surgery. Later in his travels, when the Tenth Doctor first encounters Jack Harkness, he asks if he'd gotten work done on his face, only for Jack to sarcastically reply with, "You can talk!" (TV: Utopia)
 * The Doctor calls Cassandra on Rose's Nokia "Superphone", which he previously upgraded on their first trip to the year five billion. (TV: The End of the World)
 * Rose's low-cut purple blouse, which she wears for much of the episode, is later found slung over a railing by Donna Noble when she first materialises inside the TARDIS. (TV: The Runaway Bride)
 * At Donna Noble's wedding reception, the Doctor watches a man and a blonde woman dancing and remembers catching Rose in his arms on New Earth after Cassandra leaves her body for good. (TV: The Runaway Bride)
 * The Doctor will again encounter Novice Hame and the Face of Boe on his next visit to New New York, thirty years later. (TV: Gridlock)
 * The Doctor is able to tell when a companion is not themselves. They would go on to show a knack for this, quickly identifying Martha's clone (TV: The Poison Sky) and recognising Amy Pond as a Ganger in their eleventh incarnation. (TV: The Almost People)
 * The Doctor will revisit Novice Hame for the last time on her deathbed. (WC: The Secret of Novice Hame)

DVD releases

 * This episode was released as a "vanilla" DVD with The Christmas Invasion. It was later released as part of the Series 2 DVD box set.
 * This story was also released with Issue 8 of the Doctor Who DVD Files.