2005

The year 2005 was most significant for being the year in which the central London on Earth was attacked by the Nestene Consciousness. (DW: Rose) The FLIPback Project began at the Snowcap Base at Earth's South Pole in order to counter the predicted reversing of the Earth's magnetic field in 2006. (NA: Iceberg)

January

 * 01 - Rose Tyler encounters a man who predicts that she will have a great year ahead. Unknown to her, this man is the tenth incarnation of the Doctor, an individual whom she had yet to meet. After she departed, the Doctor begins to succumb to radiation poisoning and staggers towards his TARDIS, encouraged by a vision of Ood Sigma. After dematerializing the TARDIS, he regenerated into his eleventh incarnation and begins to crash the TARDIS due to the nature of the regeneration.(DW: The End of Time)
 * Since the regeneration occurred after the Doctor dematerialised the TARDIS, it is unclear whether the event actually occurred on 1st January 2005.

February

 * Annual de-frosting of Tommy Brockless, a young soldier first cryogenically frozen in 1918. (TW: To the Last Man.) (Date: WEB:torchwood.co.uk)

March

 * Monday (exact date unknown) - The Ninth Doctor is in London pursuing the Nestene Consciousness. His investigations take him to the Henrik's department store where he saved Rose Tyler from an Auton attack. He then blows up the building. (DW: Rose)
 * Tuesday (exact date unknown) - With the help of his new companion Rose Tyler, the Ninth Doctor stops a third attempt to conquer Earth by the Nestene Consciousness, recently reduced from a marauding race of conquerors to desperate refugees by the Last Great Time War. Rose joins the Doctor on his travels. (DW: Rose)
 * Clive Finch's website "Who is Doctor Who?", dedicated to uncovering the mystery of a man seen in historical photographs going back more than a century, is left without a webmaster when Clive is killed by Autons. (DW: Rose)
 * Wednesday (exact date unknown) - Rose contacts her mother Jackie from the year 5,000,000,000 using the superphone and made a brief return trip to her own time (DW: The End of the World), but thereafter she disappears until 2006. After this time her boyfriend, Mickey Smith, is initially held as a suspect in her possible murder; Mickey subsequently took over running the "Who is Doctor Who?" website. (DW: Aliens of London)
 * Some time after this, London, cabs are replaced with motorcycles in an attempt to relieve the increasing traffic congestion (NA: Cat's Cradle: Warhead)

June

 * Der Spiegel magazine gave away a personal organiser with every issue (NA: Transit)

Unknown dates

 * The FLIPback Project begins at the Snowcap Base at Earth's South Pole, at the same time that Cybermen left over from the attack on Earth in 1986 once more become active. (NA: Iceberg)
 * London police, including DI Billy Shipton, begin investigating the disappearance of a number of people who visited an old abandoned house called Wester Drumlins. The police begin collecting as evidence the vehicles left abandoned by the disappeared, at one point obtaining a police box from the scene. The case would remain unsolved until 2007. (DW: Blink)
 * For most of 2005, Mickey Smith lived with accusations that he had kidnapped or killed Rose Tyler. He was taken in for police questioning about Rose's disappearance five times from early 2005 to early 2006. Jackie Tyler fuelled the mistrust of Smith around the Powell Estate by starting a "whisper campaign" against him. For Jackie, though, the year wasn't spent just accusing Smith. It was also a year in which she devoted considerable time to the actual search for her daughter. (DW: Aliens of London)

January

 * EDA: To the Slaughter was first published. With the new Doctor Who TV series about to premiere, BBC Books had decided to retire both the BBC Eighth Doctor Adventures and BBC Past Doctor Adventures lines, in favour of a new series of novels featuring the Ninth Doctor. One more EDA book will follow in June, while the PDA series will continue to the end of 2005 (one of which will be an Eighth Doctor story).
 * BFA: The Juggernauts was first released.
 * BFU: Snake Head was first released.
 * 17 - DW: Horror of Fang Rock was released to DVD in the UK.
 * 29 - Big Finish Productions announced the production of three standalone hardback novels as part of its Big Finish New Worlds range. These are BFIW: Wildthyme on Top, BFNW: Project: Valhalla and BFNW: The Coming of the Queen. Big Finish also announced that it will be producing two single audio stories featuring Iris Wildthyme
 * Sophie Okonedo, who provided the voice of Alison Cheney in the webcast WC: Scream of the Shalka, was nominated for the Best Supporting Actress Academy Award for her role in the 2004 film, Hotel Rwanda. Okonedo became the first actor to have played a Doctor or companion in an official Doctor Who production to have been nominated for an Oscar. She ultimately did not win.
 * At some point in January, the BBC was made aware that Christopher Eccleston was not taking part in a second series of Doctor Who. According to a 4th April press release, the BBC agreed not to announce this to the public. It was later revealed that Russell T Davies had hoped to keep the actor's departure a secret until the regeneration in DW: The Parting of the Ways was broadcast.

February

 * PDA: Match of the Day was first published. This was the final BBC Past Doctor Adventures novel to feature the Fourth Doctor and, as of 2009, this was the most recent original Fourth Doctor novel. The PDA series was suspended until July to allow for the premiere and broadcast of the first season of the revived series.
 * BFA:The Game was first released.
 * 03 - DW: Ghost Light was released to DVD in Region 4.
 * 05 - At the conclusion of a Saturday Night Live sketch on public access television pledge drives, TV celebrity Paris Hilton dons the Fourth Doctor's hat and scarf and made reference to the Daleks and the TARDIS. The sketch was widely circulated among SF fandom, in part via the recently introduced video-sharing website, YouTube. In the coming years, YouTube became a major outlet for the distribution of fan-made music videos, clips and other material related to Doctor Who and its spinoffs.
 * 10 - Leonard Trolley (Supt. Reynolds in DW: The Faceless Ones) died in England.
 * 11 - The Doctor Who Information Network (DWIN), the main Canadian Doctor Who fan club, launched its News Blog website.
 * 16 - The TARDIS Index File Wikia website was launched.

March

 * BFA: Dreamtime was first released.
 * ST: Short Trips: Seven Deadly Sins was first published.
 * BFU: The Longest Night was first released.
 * This month, promotion for the upcoming return of Doctor Who to television enters high gear.
 * 01 - DW: The Visitation and The Green Death was released to DVD in Region 1.
 * As early reviews of the new Doctor Who series begin to appear, IGN Filmforce that the American cable broadcaster Sci-Fi Channel, considered the most likely US broadcast home for the series, had chosen not to purchase it. Although there was talk of a related cable network, Universal HD, picking up the series, for the time being United States viewers will not be able to see the new series, with the exception of those close enough to Canada to receive the CBC broadcasts, which will now be the North American premiere of the series.
 * 07 - DW: The Mind Robber was released to DVD in the UK.
 * 08 - Big Finish Productions announced it had agreed to a deal with Paul Cornell allowing the company to continue its range of Bernice Summerfield books and audio CDs for the next few years.
 * 09 - BBC Radio 4's Today runs a feature on the new series.
 * 12 - Whether by coincidence or by design (as the impending change of lead actor was already known behind the scenes), this week's cover of Radio Times featured yet-to-be-announced Tenth Doctor actor David Tennant in a very Doctor-like pose promoting the mini-series Casanova - right next to a headline promoting the return of Doctor Who. This was the first of numerous Radio Times covers for Tennant over the next few years.
 * 22 - Project Who Bigger on the Inside, the first episode of a two-part behind-the-scenes documentary on the return of Doctor Who, was first broadcast on BBC Radio 2 (later released on the CD Project: WHO?).
 * 23 - Billie Piper interviewed on The Chris Moyles Show on BBC Radio 1
 * 25 - Christopher Eccleston interviewed on Friday Night with Jonathan Ross.
 * 26 - DW: Rose was first broadcast, returning Doctor Who to television as a weekly series for the first time since 1989 and launching Series 1, aka Season 27. Christopher Eccleston debuts as the Ninth Doctor, along with Billie Piper as companion Rose Tyler.
 * In conjunction with the debut of the new series, BBC Three premiered its behind-the-scenes series, Doctor Who Confidential the same night. A new episode of Confidential follows the broadcast of each new episode of Doctor Who.
 * The Doctor Who Story Broadcast on UK Gold.
 * Radio Times features Doctor Who on its cover. With the arrival of the news series, the Radio Times begins featuring the series on a more frequent basis (something not seen since the early 1970s).
 * 29 - Project Who: Reverse the Polarity, part 2 of the BBC Radio 2 documentary series, was first broadcast (later released on the CD Project: WHO?).
 * 30 - The BBC announced production to go ahead on a second series and a Christmas Special.
 * A publicity branch of the BBC prematurely announced that Christopher Eccleston would not be returning for a second series as the Doctor, citing his desire to not be typecast. This reason was immediately denied by Eccleston and the BBC ultimately retracted it (as of 2009 he had never confirmed his reason for leaving the role). In his 2008 book The Writer's Tale, Russell T Davies confirms that Eccleston's departure was intended to be kept secret until the final moments of DW: The Parting of the Ways.

April

 * BFA: Three's a Crowd was first released.
 * BFG: Lies was first released. This audio drama featured the landmark first meeting between the first two incarnations of Romana, featuring Mary Tamm returning to the role of Romana I.
 * 2 - DW: The End of the World was first broadcast.
 * 4 - The BBC retracted part of its 30th March announcement regarding the departure of Christopher Eccleston, indicting it had released the information with incorrect attribution and without the actor's consent.
 * 7 - DW: Horror of Fang Rock was released to DVD in Region 4.
 * 9 - DW: The Unquiet Dead was first broadcast. First appearance of the Rift; first revival-series story set in Wales; first appearance of Eve Myles in the Doctor Who franchise.
 * 16 - DW: Aliens of London was first broadcast. This episode was significant for reintroducing UNIT (last referenced on television in DW: Battlefield) and for establishing that all modern-day stories in the Doctor Who franchise from this point on (spinoffs included) take place approximately one year ahead of their real-life broadcast date. First appearance of the Slitheen. For the first time since DW: The Gunfighters, a multi-part story carried different episode titles.
 * David Tennant was officially announced as the Tenth Doctor. At this time Tennant was best known for playing the title role in Casanova, a BBC miniseries that had been produced by Russell T Davies. He had also recently filmed a role in Harry Potter and the Goblet of Fire which would be released to theatres the same day that his first solo performance as the Doctor was broadcast.
 * 21 - THN: Echoes was first published.
 * 23 - DW: World War Three was first broadcast.
 * 25 - DW: The Claws of Axos was released to DVD in the UK; this was the first classic series DVD release in the UK since the revival of the series began.
 * 30 - DW: Dalek was first broadcast. The Daleks make their revived-series debut. Bruno Langley briefly joined the series as short-term companion Adam Mitchell.
 * The Canadian Broadcasting Corporation in Canada began airing the new series, the first time the CBC had aired Doctor Who since the mid-1960s. For the CBC broadcasts, Christopher Eccleston videotapes special introductions and promotions for a contest sponsored by TV Guide, the first prize being a trip to London to visit the set of Doctor Who. These broadcasts were promoted as the North American debut of the series, as no other broadcaster on the continent had yet picked up the revived series.
 * Christopher Eccleston became a Mencap charity ambassador.

May

 * BBC Books launched the New Series Adventures line of original novels tying in with the new series; this line, featuring the Ninth Doctor, replaced the BBC Eighth Doctor Adventures and BBC Past Doctor Adventures lines, though both continue publishing briefly. The new line of books are published in hardcover and have a shorter word count than the EDA/PDA novels. The books were to be released three at a time. The first three released were NSA: The Clockwise Man, NSA: The Monsters Inside, and NSA: Winner Takes All.
 * BFA: Catch-1782 was first released.
 * ST: Short Trips: A Day in the Life was first published.
 * BFG: Spirit was first released.
 * BBCR: Project: WHO? was first released by BBC Audio. This was a CD issue of the two-part BBC Radio documentary Project Who on the return of Doctor Who, featuring interviews with Christopher Eccleston, Billie Piper and others.
 * 5 - DW: The Mind Robber was released to DVD in Region 4.
 * 7 - DW: The Long Game was first broadcast. Bruno Langley departed the series as his character, Adam Mitchell, became the first TV companion to be forced out by the Doctor.
 * 14 - DW: Father's Day was first broadcast.
 * 16 - In the UK, BBC Video released Doctor Who: Volume 1 with the episodes DW: Rose, The End of the World and The Unquiet Dead. This was the first of a series of "vanilla" (extras-free) DVD released BBC Video featuring episodes from a still-underway season and these are the first new-series episodes (and first Ninth Doctor episodes) to be released to home video.
 * 21 - DW: The Empty Child was first broadcast. John Barrowman made his first appearance as Jack Harkness. This episode, and part 2 the next week, are Steven Moffat's first serious contributions to televised Doctor Who and will win the series its first Hugo Award.
 * 28 - DW: The Doctor Dances was first broadcast. The character of Jack Harkness was introduced.

June

 * EDA: The Gallifrey Chronicles was first published. This was the final release in the BBC Eighth Doctor Adventures novel series, as BBC Books prepared to move into publishing novels exclusively based upon the revived series. One further Eighth Doctor novel will be published under the BBC Past Doctor Adventures line.
 * BFA: Unregenerate! was first released.
 * BFG: Pandora and BFG: Insurgency are first released.
 * BFU: The Wasting was first released. Final episode of the spin-off series, U.N.I.T..
 * BFBS: The Tree of Life was first published.
 * FP: Warring States was first published.
 * The BBC announces that a second Christmas special had already been commissioned for 2006, as well as a third season for the new Doctor Who series.
 * 01 - Geoffrey Toone (Hepesh in DW: The Curse of Peladon and Temmosus in Dr. Who and the Daleks) died in Northwood, Middlesex, England.
 * 02 - DW: The Claws of Axos was released to DVD in Region 4.
 * 04 - DW: Boom Town was first broadcast.
 * 07 - DW: The Leisure Hive was released to DVD in Region 1.
 * 08 - Ed Bishop died. He played General Flint in DWU: Full Fathom Five and was best known as Ed Straker in UFO and Captain Blue in Captain Scarlet and the Mysterons.
 * 11 - DW: Bad Wolf was first broadcast. First reference to Torchwood.
 * Christopher Eccleston was interviewed by BBC Radio.
 * 13 - The DVD Doctor Who: Volume 2 was released by BBC Video featuring the new series episodes DW: Aliens of London, World War Three and Dalek.
 * 18 - DW: The Parting of the Ways was first broadcast, concluding the first season of the revival of Doctor Who. The Ninth Doctor regenerated into the Tenth, introducing David Tennant and marking Christopher Eccleston's final (to date) appearance as the Doctor. John Barrowman also departed the series as a regular with this story. The broadcast was followed by the final transmission of Doctor Who Confidential's first season.
 * Post-production completed for DW: The Christmas Invasion.
 * 21 - DW: Ghost Light was released to DVD in Region 1.

July

 * PDA: Island of Death was first published. Final PDA novel to feature the Third Doctor and last Third Doctor original novel to date. The PDA series returns to monthly released for the remainder of the year as the final books in the line are published.
 * BFA: Terror Firma was first released.
 * MB: Coming to Dust: The True History of Faction Paradox Volume 1 was first released. The Faction Paradox series was now being produced by Magic Bullet Productions.
 * 11 - DW: Revelation of the Daleks was released to DVD in the UK. Beginning with this release, BBC Video issued Doctor Who DVDs in conjunction with 2 entertain.
 * 15 - The first performance of the Doctor Who - Inside the TARDIS live stage tour was held at the Robert Blackwood Hall in Melbourne, Australia.
 * 16 - The second performance of the Doctor Who - Inside the TARDIS live stage tour was held at the Palais Theatre in Melbourne, Australia.
 * 17 - The third performance of the Doctor Who - Inside the TARDIS live stage tour was held at the Palais Theatre in Melbourne, Australia.
 * 21 - THN: Peculiar Lives was first published.
 * The fourth performance of the Doctor Who - Inside the TARDIS live stage tour was held at the Burswood Theatre in Perth, Australia.
 * 23 - The fifth performance of the Doctor Who - Inside the TARDIS live stage tour was held at the Festival Theatre in Adelaide, Australia.
 * 25 - The BBC announced that Elisabeth Sladen would be returning to the role of Sarah Jane Smith for an upcoming episode of the revived Doctor Who's second series.
 * 26 - The sixth performance of the Doctor Who - Inside the TARDIS live stage tour was held at the Canberra Theatre in Canberra, Australia.
 * 29 - The seventh performance of the Doctor Who - Inside the TARDIS live stage tour was held at the Theatre Royal in Sydney, Australia.
 * 30 - The eighth performance of the Doctor Who - Inside the TARDIS live stage tour was held at the Theatre Royal in Sydney, Australia.

August

 * PDA: Spiral Scratch (originally promoted under the title Future Nostalgia) was first published. Final novel to date to feature the Sixth Doctor.
 * BFA: The Council of Nicaea was first released.
 * BFG: Imperiatrix was first released.
 * 01 - The DVD Doctor Who: Volume 3 featuring the episodes DW: The Long Game, Father's Day, The Empty Child and The Doctor Dances.
 * The ninth performance of the Doctor Who - Inside the TARDIS live stage tour was held at the Brisbane Convention Centre in Brisbane, Australia.
 * 5 - The tenth performance of the Doctor Who - Inside the TARDIS live stage tour was held at the Westpac St James Theatre in Wellington, New Zealand.
 * 6 - The last performance of the Doctor Who - Inside the TARDIS live stage tour was held at the Civic Theatre in Auckland, New Zealand.
 * 31 - Michael Sheard, who had countless roles in Doctor Who, notably DW: Pyramids of Mars and DW: Remembrance of the Daleks, died of cancer on the Isle of Wight.

September

 * NSA: The Deviant Strain, NSA: Only Human, and NSA: The Stealers of Dreams are first published. To date, these are the last novels featuring the Ninth Doctor as BBC Books changes to novels featuring the Tenth Doctor.
 * PDA: Fear Itself was first published. This was the last novel to date to feature the Eighth Doctor and was the only time this incarnation was featured in the BBC Past Doctor Adventures line.
 * BFA: Thicker Than Water was first released.
 * BFA: LIVE 34 was first released.
 * ST: Short Trips: The Solar System was first published.
 * BFC: Scorpius the first episode of a new Big Finish Productions spin-off series, Cyberman, was first released.
 * Doctor Who Annual 2006 was first published. This marks the return of the Doctor Who Annual, a once-traditional publication that was issued during most of the run of the original series. Marvel Comics had last made an attempt at reviving the format in the early 1990s.
 * 01 - DW: Revelation of the Daleks was released to DVD in Region 4.
 * 05 - BBCR: Doctor Who at the BBC Volume 3 was first released, including the first release of an unbroadcast Third Doctor audio mini-episode recorded for Glorious Goodwood.
 * BBC Video released the DVD Doctor Who: Volume 4 featuring the episodes DW: Boom Town, Bad Wolf and The Parting of the Ways. This concluded the series of "vanilla" DVD released of episodes from the first revival season. Discounting the unique case of the Eighth Doctor, the Ninth Doctor became the first Doctor to have his complete era released to DVD.
 * 09 - DW: The Web Planet was released to DVD in the UK.
 * 12 - Ronald Leigh-Hunt (Commander Julian Radnor in DW: The Seeds of Death and Commander Stevenson in DW: Revenge of the Cybermen) died.
 * 23 - Roger Brierley (Trevor in DW: The Daleks' Master Plan and voice of Drathro in DW: The Mysterious Planet) died after suffering a heart attack.

October

 * PDA: World Game was first published. Final Second Doctor novel to date.
 * BFA: Scaredy Cat was first released.
 * BFC: Fear was first released.
 * 06 - BBC Video released a special Dalek Collector's Edition DVD box set exclusively in UK W H Smith stores. The set included the previously released DW: The Dalek Invasion of Earth, Resurrection of the Daleks and Remembrance of the Daleks.
 * 18 - John Hollis (Sondergaard in DW: The Mutants) died from natural causes.
 * 24 - Robert Sloman, who along with Barry Letts, wrote DW: The Dæmons, DW: The Time Monster, DW: The Green Death and DW: Planet of the Spiders died. (The pair were credited as "Guy Leopold" on the first story but for the final three, Sloman took the sole credit.)

November

 * PDA: The Time Travellers was first published. Final First Doctor novel to date.
 * BFA: Singularity was first released.
 * BFIW: Wildthyme at Large was first released, launching an ongoing series of audio dramas featuring the character of Iris Wildthyme, played by Katy Manning.
 * 03 - DW: The Web Planet was released to DVD in Region 4.
 * 06 - DW: Horror of Fang Rock, The Mind Robber and The Claws of Axos are released to DVD in Region 1.
 * 07 - BBC Audio released Travels in Time and Space, a box set collecting three unabridged readings of early novelisations: Doctor Who in an Exciting Adventure with the Daleks, Doctor Who and the Zarbi and Doctor Who and the Crusaders, all read by William Russell.
 * DW: City of Death was released to DVD in the UK.
 * 18 - The DW: Children in Need Special was broadcast by the BBC as part of the Children in Need Appeal, marking the first solo appearance by David Tennant as the Tenth Doctor. This 7-minute mini-episode bridges the events of DW: The Parting of the Ways and DW: The Christmas Invasion and was the first canonical production of this nature (an earlier CiN production, 1993's DW: Dimensions in Time, was not generally considered part of the canon). It became the first production of the series revival not to be broadcast outside of the UK (though it was later included on international DVDs).
 * Harry Potter and the Goblet of Fire was released to cinemas in the US and UK, featuring new Doctor David Tennant in a key role.
 * 21 - The complete Series 1 (2005) of Doctor Who was released to DVD in the UK as a box set. This was the first time a complete season of Doctor Who was been released all at once (although all episodes had been issued previously in vanilla editions). Included was a bonus disc featuring the first DVD release of episodes of Doctor Who Confidential, although due to licensing and appearance rights issues, the practice of releasing edited-down versions (retitled Doctor Who Confidential Cutdown) to DVD was begun.
 * The first Region 1 (North American) release
 * 29 - Joseph Fürst (Professor Zaroff in DW: The Underwater Menace) died in Sydney, New South Wales, Australia.

December

 * PDA: Atom Bomb Blues was first published. This novel featuring the Seventh Doctor was the final release in the BBC Books Past Doctor Adventures line. After this point, BBC Books published only novels based upon the current series of Doctor Who, and also moved away from the paperback format, adopting a hardcover format (with the exception of Quick Reads novellas) hereafter. As of the fall of 2009, Atom Bomb Blues was the last novel to be published featuring a Doctor other than the one currently on TV.
 * BFA: Other Lives was first released.
 * ST: Short Trips: The History of Christmas was first published.
 * BFC: Conversion was first released.
 * BFIW: The Devil in Ms. Wildthyme was first released. Last Iris Wildthyme audio drama until 2009.
 * 01 - DW: City of Death was released to DVD in Region 4.
 * 08 - David Tennant appears on BBC Radio 4's Front Row.
 * 19 - Don McKillop (Bert the Landlord in DW: The Dæmons) died from natural causes in the UK.
 * 21 - David Tennant appears on BBC One's Breakfast programme.
 * 23 - BBC Radio Wales broadcasts Back in Time - New Doctor, New Danger, featuring Russell T Davies and others.
 * The BBC Two comedy series Dead Ringers featured the parody "Christmas at Doctor Who's" featuring the cast impersonating David Tennant, Tom Baker, Sylvester McCoy, Patrick Troughton and Christopher Eccleston.
 * 25 - DW: The Christmas Invasion was first broadcast, officially launching the Tenth Doctor era. The episode closing credits introduce a modified arrangement of the Doctor Who theme restoring the "middle 8" section not used during Series 1. At the behest of star David Tennant, the lead character was once again identified in the closing credits as "The Doctor".
 * Following the broadcast, the BBC's "Red Button" service made available WC: Attack of the Graske, an interactive mini-episode-cum-game featuring David Tennant. Initially this was only available for viewing/playing in the UK.
 * 26 - DW: The Christmas Invasion airs on the CBC in Canada. For this broadcast, Billie Piper videotapes a special introduction. This marks the last time (to date) that the CBC's broadcasts of the series more-or-less coincide with that of the BBC.
 * 27 - BBC Radio 4's Front Row runs a feature on the new Doctor.

Unknown dates

 * Broadcast of the revived series in the United States was delayed when the American Sci-Fi Channel unexpectedly passed on picking up the series. Reasons cited in media and fan forums included the show being considered "too British" and concerns over the quality of the preview episodes seen. Sci-Fi eventually reversed its decision and the series was broadcast at a later date and the network subsequently picks up further seasons in a more timely manner.
 * Following the conclusion of the 2005 Doctor Who series, the BBC announced that it had commissioned the franchise's first full spin-off series, Torchwood, to debut in 2006 and star John Barrowman, reprising his role of Jack Harkness.
 * Autumn: During production of the 2006 series, the media reports that Billie Piper would leave the series at the end of the season.