The Doctor, Martha and Jack escape back to modern-day Earth, where they discover that the Master -- masquerading as Harold Saxon -- has just been elected Prime Minister of Great Britain. Before they can intervene, the Master announces to the world that Britain has made first contact with an alien species: the Toclafane. But the Toclafane are not the benevolent creatures the Master is pretending... and with the Doctor declared public enemy number one, it looks like there may be nothing to come between his Time Lord nemesis and the end of the world.

Very early in the process of developing ideas for the new Doctor Who series in 2004, executive producer Russell T Davies conceived the idea of a monster which would take the form of a small, flying sphere. Possessing the personality of a sadistic child, this would in fact be a human from the end of time, horribly mutated. For a considerable period, the monster possessed neither a name, nor a story in which to appear. Davies considered using it in both Dalek and The Satan Pit when those stories ran into issues with their monsters (the temporary loss of the rights to use the Daleks, and concerns over the expense of computer-animating the Beast, respectively), although in the end his own creation remained on the shelf. Ultimately, Davies' monster -- now called the Toclafane (originally, Roclafane, but changed to avoid similarities with the Racnoss from The Runaway Bride) -- became the first element conceived for Doctor Who's 2007 season finale.

Meanwhile, Davies had become intrigued by the Rogue Traders song Voodoo Child. He had decided that the Master would feature prominently in the wrap-up to his third season at the helm of Doctor Who, and he found that the song helped him to crystallise his perception of the evil Time Lord. Even before he had begun writing his scripts, Davies had the song cleared for use in the programme. Indeed, Voodoo Child's lyric “Here it comes, the sound of drums” provided the first episode with its title: The Sound Of Drums. The final installment, meanwhile, became known as Last Of The Time Lords; Davies was writing these scripts by December 2006.

As in the preceding episode, Utopia, Davies wanted to both compare and contrast the Doctor and the Master, and so created the character of Lucy Saxon to fill the role of the Master's “companion”. Davies also incorporated elements of previous Doctors in the Master's behaviour (such as his eating jelly babies, a trait of Tom Baker's Fourth Doctor), while recalling former Masters as well. The speech in The Sound Of Drums which began, “Peoples of the Earth, please attend carefully,” paralleled a similar pronouncement in the 1981 serial Logopolis, while the Master's fascination with The Teletubbies harkened back to 1972's The Sea Devils, in which he was seen to be watching The Clangers, another children's programme.

Meanwhile, during the second of half of 2006, Davies decided that Martha Jones would leave the Doctor in Last Of The Time Lords. An ongoing element of Martha's character arc was her unrequited love for the Doctor, and Davies felt that this would become stale if it were to carry over into the 2008 season. He therefore decided to give Martha a break from travelling in the TARDIS, with a view to bringing the character back -- a little older and wiser -- partway through the subsequent season. (Martha would also appear in Torchwood in the interim.)

Originally, Downing Street played a much larger role in the story, serving as the location for the last of Martha's decoy chemicals. At this stage, Milligan was in fact a traitor, who was killed after betraying Martha to the Master. Davies began to feel that the world of the ravaged Earth deserved greater exploration, however, and concocted the material involving Professor Docherty instead. Leo Jones was also intended to appear in Last Of The Time Lords, welcoming Martha back to Britain and introducing her to Milligan. This had to be changed due to Reggie Yates' scheduling conflicts, which meant that he could only spare one recording day for Doctor Who; instead, dialogue now referred to Leo working in the Master's slave force under an assumed name. Excised from The Sound Of Drums, albeit for reasons of cost, was a more elaborate car chase sequence.

As with 42, Saxon's female agent was originally intended to be the same man introduced in The Lazarus Experiment; this had to be changed when Bertie Carvel became unavailable. Vivien Rook was named for journalist Jean Rook, while the Archangel network was first called Angel One. Martha's suggestion that the Doctor and the Master are brothers -- dismissed by the Doctor -- was Davies' response to a popular fan theory he found rather daft. The final scene with Jack was written to include dialogue between him and the Doctor which playfully poked fun at the John Barrowman voice-over accompanying each episode of Torchwood. This was removed because it was felt to be too metatextual.

As had now become traditional, The Sound Of Drums / Last Of The Time Lords boasted several celebrity cameos, this time famous figures declaring their support for Harold Saxon. These included Sharon Osbourne (host of the The X Factor and star of The Osbournes alongside her husband, heavy metal icon Ozzy Osbourne), pop group McFly, and Ann Widdecombe (Conservative MP and presenter of The Widdecombe Project). Meanwhile, Davies had forgotten his intention to include Voodoo Child in the broadcast of the story. He was reminded only at a late stage by script editor Simon Winstone, who had long obtained the appropriate clearances, and the song was duly inserted into The Sound Of Drums.

The season finale formed the eighth and final block of Doctor Who's recording schedule. The director assigned to The Sound Of Drums / Last Of The Time Lords was Colin Teague, who had previously helmed Ghost Machine and Greeks Bearing Gifts for Torchwood, as well as Invasion Of The Bane for The Sarah Jane Adventures. Teague began filming the story on February 7th at the Upper Boat Studios, when David Tennant's performance as the diminutive, methuselan Doctor was motion-captured for computer animation. Two days later, the flashback material in Professor Yana's laboratory was taped at Upper Boat, while the segments featuring the various international news anchors were completed at BBC Wales.

The first major location for The Sound Of Drums / Last Of The Time Lords was Hensol Castle in Hensol. Recording there from February 15th to 17th covered scenes in the rebuilt Downing Street, as well as Vivien Rook's study, the Toclafane's address to humanity, and the American university dorm room. Adjacent houses on Cwrt-y-Vil Road in Penarth served as Francine's and Clive's homes on the 19th; the scene of the mother (played by Teague's wife, Marjorie) and baby watching television was also shot in the latter location. Leo receiving Martha's warning was then performed at the Esplanade in Penarth, while Sharon Osbourne's cameo was directed by Susie Liggat (who had produced Huamn Nature / The Family Of Blood earlier in the season) in Buckinghamshire. February 20th again began at Cwrt-y-Vil Road, before continuing the car chase on other Penarth streets.

The return of the Doctor, Martha and Jack from the far future was filmed on February 21st at The Friary in Cardiff, followed by Jack's final scene in Millennium Square. The day concluded with the Master's election victory address, conducted inside the Millennium Centre. On the 22nd, the Roundwood area of Cardiff was the locale where Martha's car was abandoned. Meanwhile, the McFly and Ann Widdecombe cameos were taped by Liggat in London, at Universal Music and before the Houses of Parliament, respectively. February 23rd was spent at Upper Boat, concentrating on scenes in Martha's flat, as well as the TARDIS console room.

Recording at Upper Boat continued from February 26th to March 1st, on the sets of both the TARDIS and the Valiant flight deck. The final day also included a trip to the Caerphilly Mountains, where Martha arrived after escaping the Valiant. March 2nd started at University Place in Cardiff, for material outside Martha's flat; cast and crew then shifted to the old NEG Glass site at Trident Park in Cardiff Bay, where the completion of scenes in the bowels of the Valiant continued to the 3rd. Three more days at Upper Boat followed from the 5th to the 7th, covering more Valiant flight deck and TARDIS scenes. The last of these was the closing shot featuring the apparent collision between the TARDIS and the Titanic, leading into the 2007 Christmas special, Voyage Of The Damned. This was taped with only minimal crew present, in order to maintain secrecy about the special's contents.

The venue on March 8th was Vaynor Quarry near Merther Tydfil: here, Martha and Milligan spied on the rocket silos, the Doctor and the Master had their climactic confrontation, and the Master's funeral pyre burned. A late addition to the script was the woman's hand (actually production manager Tracie Simpson) picking up the Master's ring while the evil Time Lord's laughter echoed. Davies had decided to include this shot in order to give future production teams a mechanism by which they could bring the Master back. On March 9th, RAF St Athan provided the airstrip, as well as the exteriors of the factory and Professor Docherty's shed. The hideout to which the Doctor, Martha and Jack retreat was actually a British Rail warehouse in Cardiff; these scenes were recorded on the 10th, and marked the end of both David Tennant's and John Barrowman's work on the season.

Freema Agyeman, however, still had work to do covering Martha's quest on the enslaved Earth in Last Of The Time Lords. This began on March 12th, when Freema's return to Britain was filmed at Barry Island Beach. This day also saw the shots of the old Time Lord and the juvenile Master performed. The Time Lord was dressed in the Gallifreyan robes which had been traditional since The Deadly Assassin in 1976, and in fact the headpiece was a prop from the original Doctor Who series. Meanwhile, at the suggestion of script editor Gary Russell, the Master's outfit reflected the earlier Time Lord costumes established in 1969's The War Games.

March 13th was the final day at Upper Boat, covering the remaining scenes on the Valiant flight deck and the Master's television broadcast, plus a remount of the woman (once again Tracie Simpson) recovering the Master's ring. Two Cardiff locations were visited on the 14th: Cathays Park was the site of Martha's meeting with Professor Docherty in the episode's coda, while South Luton Place provided the house where Martha passed along the Doctor's story and the slaves intoned the Doctor's name.

On March 15th, Teague was injured in a fall at his home, and so Graeme Harper (who had just finished 42 and Utopia) made himself available to direct the remaining scenes. His first two days saw a return to the NEG Glass site, posing as the interior of Docherty's shed, the factory and Milligan's hospital; March 16th brought Agyeman's time as a Doctor Who regular to a close. Then, on the 19th, the season's final material -- in the cafe at the end of The Sound Of Drums -- was completed. This had originally been scheduled for Mac's Cafe in Cardiff on March 1st, but had been postponed and was now recorded at Forte's Cafe on Barry Island.

With Doctor Who continuing to be extraordinarily popular, the BBC consented to an overlong edit of Last Of The Time Lords. This would now be screened in a 50-minute timeslot, rather than the 45-minute duration of a typical Doctor Who episode. (A 45-minute version was still prepared for international sales, however.) The new Doctor Who series' third season came to an end on June 30th. This gave the programme a hat trick of Top Ten finishes for the year, suggesting that the viewing public was still as eager as ever for the Doctor's next great adventure...

• Outpost Gallifrey: New Doctor Who Series News Page, edited by Shaun Lyon.
• Doctor Who Magazine Special Edition #17, 22nd November 2007, “Episodes 12 & 13: The Sound Of Drums / Last Of The Time Lords” by Andrew Pixley, Panini Publishing Ltd.