Returning to Earth in the modern day, the Doctor and Rose discover that humanity has embraced what are believed to be ghosts come back from the dead. Suspicious, the Doctor follows the trail of the ghosts to the headquarters of the sinister Torchwood Institute, which has been established to deal with alien incursions on British soil. But Torchwood itself has been compromised, and may be the first casualty in a transdimensional war which will engulf the Earth -- a war between the Cybermen and the Daleks.

By the end of 1967, the Daleks and the Cybermen had cemented their status as the shining stars of Doctor Who's carnival of monsters. On December 5th, an approach was made to Dalek creator Terry Nation about having both races appear together in an adventure. This was hastily vetoed by Nation (and the Cybermen-only serial The Wheel In Space was made in its place). Indeed, over the course of the original Doctor Who series, only one story -- the twentieth-anniversary special The Five Doctors -- included roles for both the Daleks and the Cybermen, and in that instance the two monsters did not even meet.

While charting the course for the second season of the revived Doctor Who programme, however, executive producer Russell T Davies hit upon the idea of ending the year with the realisation of that long-dismissed Dalek/Cyberman idea. The Daleks had already proven tremendously popular during the 2005 season, practically demanding that they be brought back the next year, and Davies had every intention of resurrecting the Cybermen for the show's sophomore season.

Such an epic conflict would also provide a suitable backdrop for the exit of Rose Tyler, made necessary by Billie Piper's decision early in 2005 to leave Doctor Who after her second season. Davies planted the seeds for Rose's departure via the mid-year introduction of the new Cybermen and the parallel Earth of their provenance, in Rise Of The Cybermen / The Age Of Steel. He had recognised the fact that only a calamity of cosmic proportions would suffice to separate the Doctor and Rose. Having ruled out the notion of simply killing Rose on the grounds of it being too demoralising, Davies instead decided to trap her in a parallel universe to which the Doctor could never return.

The two-part story which would write Rose out of Doctor Who was initially called Army Of Ghosts, and would be written by Davies himself. A crucial element of the adventure was the Torchwood Institute. This had first been mentioned in Bad Wolf the year before, the name being an anagram of “Doctor Who” created to camouflage tapes issued by the production office. Davies decided to use it as the linking element of the second season, in much the same way as “Bad Wolf” had been in 2005. Torchwood was seen in action in The Christmas Invasion; was referred to on Mickey's computer in School Reunion; appeared on Rose's mobile phone and was mentioned in conversation by Pete Tyler in Rise Of The Cybermen; was namedropped by the policemen in The Idiot's Lantern and by Victor Kennedy in Love & Monsters; was the agency responsible for the mission to the black hole in The Impossible Planet / The Satan Pit (under the guise of the Torchwood Archive); and was referenced on TV in Fear Her. Most notably, Tooth And Claw depicted the creation of the Torchwood Institute by Queen Victoria in 1879.

Davies originally intended Torchwood to be based in Cardiff, on the time rift which had been introduced in The Unquiet Dead. When a Torchwood spin-off series was commissioned in mid-2005, however, Davies took the opportunity to base that programme in Cardiff and shifted the action of Army Of Ghosts to Canary Wharf in London. Davies briefly considered calling the two episodes “Torchwood Rises” and “Torchwood Falls”, but the first installment later reverted to Army Of Ghosts while the season finale became Doomsday.

A key point of debate in Davies' scripts was the climactic moment in which Rose is saved from the Void. Davies and executive producer Julie Gardner felt that her rescuer should be Pete, since this would emphasise his acceptance of Rose as his surrogate daughter. However, some thought was given to assigning this role to Mickey, a position championed by producer Phil Collinson and Mickey actor Noel Clarke. Meanwhile, one expensive sequence removed from the script for Doomsday at the development stage involved the Doctor and Rose ascending to the top of Torchwood Tower in the Jathaa Sun Glider (described as a “space canoe”) mentioned in Army Of Ghosts; this was replaced with the much simpler moment of Jake summoning them into the lift.

The notion of the Genesis Ark needing to be activated by a time traveller was devised to give a reason for the Daleks keeping Rose and Mickey alive for so long at the start of Doomsday. Davies also thought that this provided silent motivation for why the Daleks would have chosen to appear in twenty-first century London, since it was the most likely time and place to find the Doctor or one of his associates. He opted not to make this explicit, however, since it would pile too much grief upon the Doctor in what was already a tragic story, implicating him in the many deaths.

As written, nothing physically differentiated the four Daleks, given the names Sec, Thay, Caan and Rabe (amended to Jast at a very late stage in production because it was felt to sound too much like “Ray”) in an intentional break with tradition. Production designer Edward Thomas encouraged having Sec appear in black livery, hearkening back to other Black Daleks which had taken command positions throughout the original Doctor Who series. Davies also indicated that the Cyber Leaders should have black handles on their helmets, a design element which was also in keeping with Doctor Who tradition.

To ensure the availability of Noel Clarke and Shaun Dingwall -- for whom the making of Doomsday would be the culmination of their on-screen association with Doctor Who -- it was decided to make both episodes in one epic block alongside the year's other Cyberman story, Rise Of The Cybermen / The Age Of Steel. This would be the season's third recording block, directed by Graeme Harper. Amongst the cast was Freema Agyeman, playing Adeola. Having gotten her start in theatre -- including an adaptation of the Terry Pratchett Discworld novel Lords And Ladies -- Agyeman had enjoyed a regular role in the soap opera Crossroads, and subsequently chalked up appearances in programmes including Casualty @ Holby City and The Bill.

The production team was careful not to distribute the final pages of Doomsday to any but the most essential of cast and crew. Their intent was to safeguard both the Doctor's final conversation with Rose and the cliffhanger ending, which would lead into The Runaway Bride, the 2006 Christmas special.

Filming began on November 2nd, 2005, with the Brandon Estate in Kennington, London, posing as the Powell Estate for the last time. Shots of Westminster Bridge were also taken on this day. On the 16th, the interview with purported psychic Derek Acorah (host of Most Haunted) was recorded at Tredegar House in Newport, while the appearance of the police commissioner was taped at the Doctor Who studio space of Unit Q2, also in Newport. The Tyler estate on the parallel Earth was actually a home at Coedarhydyglyn in St Nicholas. Shooting took place there on the 21st; the “Ectoshine” advertisement was filmed simultaneously.

Army Of Ghosts / Doomsday became the principal focus of the production block beginning on November 29th; this was the start of four consecutive days at Unit Q2 concentrating on material in and around the Sphere Chamber. On December 6th, the Tyler family driving through rural Norway was taped at Hoel Spencer, Brynceithyn, Bridgend, while the nearby Brackla Bunkers played host to various corridor scenes on the 7th. December 8th and 9th saw the start of work on the Lever Room set at Unit Q2. On the 10th, street scenes (including the clip from Japan) were completed at Mount Stuart Square on Cardiff Bay. Further work in the Lever Room then took place both before and after Christmas, running from December 12th to 15th and January 3rd to 5th, 2006. The Ghostwatch material with television presenter Alistair Appleton was also taped on the 4th.

January 6th was spent at HTV Studios in Culverhouse Cross, Cardiff, to film scenes in the disused Torchwood corridor. This was Agyeman's last day on the story, and by now she had caught the eye of the production team who were searching for someone to play the Doctor's new companion in the 2007 season. Piper's exit from Doctor Who was still being kept secret -- although it had been rumoured in the press for months -- and so to avoid tipping their hand, Agyeman was asked to audition for a role she was told would feature in the Torchwood spin-off series.

More footage in Mount Stuart Square was captured on the 7th, while scenes in the Torchwood hangar were enacted at RAF St Athan in Barry on the 9th and 10th. Additional material set around the Powell Estate was recorded at Loudoun Square in Gabalfa, Cardiff on January 12th. More hangar shots were completed at RAF St Athan on the 13th, in addition to greenscreen work for Rose being sucked into the Void. Parts of the conflict between the Cybermen and the British military were filmed on January 15th at Cardiff Dockside. The same day, further sequences in the corridors of the Torchwood Institute were captured at the Capital Arcade in Cardiff.

Only essential crew made the journey to Southerndown Beach, in Ogmore Vale near Bridgend, on January 16th. In addition to posing as the alien planet seen in the opening flashbacks of Army Of Ghosts, this was also the location of Darlig Ulv Stranden: Bad Wolf Bay. Although Piper still had five episodes left to film, this was nonetheless a highly emotional shoot; it was also the last day of recording for both Noel Clarke and Shaun Dingwall. Clarke, however, would maintain his association with Doctor Who -- both by appearing in some of the TARDISodes for the season and through writing the Torchwood episode Combat.

Two days at Unit Q2 then followed on January 17th and 18th, with the first day emphasising TARDIS scenes while the second day involved the sets for both the Tylers' flat and various areas of Torchwood. The 19th began with filming at a residence in Canton, Cardiff for the sequences involving the Cybermen terrorising a family, and concluded with the flashback to a seventeen year-old Rose on the bus, recorded at the Hayes in Cardiff. January 20th was spent back at Unit Q2 for various inserts. The clip from Trisha, a talk show hosted by Trisha Goddard, was taped at Teddington Studios on January 27th following a regular installment of the programme. Barbara Windsor subsequently filmed a faux EastEnders scene for Army Of Ghosts, in character as Peggy Mitchell, at the BBC Elstree Centre in Borehamwood, Hertfordshire. More inserts were recorded at Unit Q2 on March 9th.

On February 15th, Agyeman -- now aware that she had been auditioning for Doctor Who -- was cast as new companion Martha Jones. However, Davies wanted to hold off introducing the character until the start of the 2007 season. Instead, he devised the notion of having The Runaway Bride pair the Doctor with a one-off character played by a well-known actor. Eventually cast as the Bride (who at this point had not been named) was comedienne Catherine Tate. After getting her start in series such as The Bill, Tate's fame became ascendant, with roles in programmes like That Peter Kay Thing and Wild West culminating in the successful The Catherine Tate Show. At the same time, Tate continued to make appearance in dramas including Marple and Bleak House. Davies was adamant that Tate's casting come as a complete surprise to the audience, and so not even Harper was informed of the content of Doomsday's final scene until the last possible minute. This was recorded at Unit Q2, again with a skeleton crew, on March 31st while the Doctor Who wrap party was getting under way.

The last filming performed for Doctor Who's second season took place at Unit 31 of the Enfys Television Studios in Cardiff on April 11th, and consisted of a variety of pick-up shots. Ending months of speculation, the BBC finally confirmed that Piper would be leaving the show on June 15th, with Agyeman then being introduced to the press with a photocall on July 4th. Shockingly, both Army Of Ghosts and Doomsday were accorded covers of the Radio Times, the finale even being promoted with the choice of two images (featuring the Daleks and the Cybermen, respectively, with a football theme to tie in with the broadcast of the 2006 World Cup). This brought to an astounding four the number of episodes granted Radio Times covers over the course of the 2006 season, following New Earth and Rise Of The Cybermen.

For his final TARDISodes of the year, writer Gareth Roberts initially wanted to feature profiles of the Doctor and Rose to accompany Army Of Ghosts and Doomsday, respectively. The former would have come in the shape of clips from a Torchwood training video, while the latter was to involve Jackie discussing her daughter. Roberts' first idea for the Doomsday TARDISode culminated with the Doctor laying flowers at what are revealed to be Rose's and Jackie's graves; later, he conceived the notion of having the TARDISode take the form of a dating service advertisement, with the man watching it ultimately attacked by a Cyberman. In the end, however, the 58-second TARDISode for Army Of Ghosts featured a reporter delving into the history of Torchwood, only to be betrayed by his editor and committed to an asylum. Its Doomsday counterpart, also 58 seconds long, showed a news anchor reporting on the Cyberman invasion, whereupon her studio is attacked by the Daleks.

Doomsday was broadcast on July 8th, drawing the revived Doctor Who series' second season to a close. The programme had managed to maintain the popularity of its inaugural year, despite the fact that the entire cast of regular and supporting characters introduced in Rose had now departed. Modern audiences seemed to have smoothly accepted a new Doctor. The question now raised was whether they could grow accustomed to a change in the companion, the very character who represented their window into the universe of Doctor Who.

• Outpost Gallifrey: New Doctor Who Series News Page, edited by Shaun Lyon.
• Doctor Who Magazine Special Edition #14, 9th November 2006, “Episodes 12 & 13: Army Of Ghosts / Doomsday” by Andrew Pixley, Panini Publishing Ltd.