The TARDIS brings the Doctor and Martha to New York City in the early days of the Great Depression. There they are alerted to a rash of disappearances amongst a “Hooverville” transient community by Solomon, its unofficial mayor. Investigating, the time travellers discover genetically-engineered Pig Men living in the sewers. Their masters are none other than the Daleks who, with the help of the wealthy Mr Diagoras, have perverted the construction of the Empire State Building. The Daleks plan to spearhead the next stage in their race's evolution -- a transformation with terrible ramifications for humanity.

Russell T Davies' first two seasons as Doctor Who's executive producer had included Dalek stories set in the near-future (Dalek), the far-future (Bad Wolf / The Parting Of The Ways) and the present day (Army Of Ghosts / Doomsday). For Season Twenty-Nine, he decided that it was time to place the Doctor's arch-enemies against the backdrop of Earth's history. Davies felt that this approach had been very successful on the few occasions that it had previously been attempted -- most notably in 1967's The Evil Of The Daleks, which took place a century earlier. This time, Davies envisaged a two-part adventure set in 1930 New York City, a year after the start of the decade-long economic slump known as the Great Depression. He wanted to focus on the fact that the Daleks were genetically engineered, which he imagined would make them skilled in the discipline. Thus they would be served by human-pig hybrids, which were originally the results of experimentation on kidnapped sailors; Davies hoped that the Cardiff Docks could be made to look like their Gotham equivalents.

To write the new Dalek story, Davies approached Steven Moffat, who had most recently scripted The Girl In The Fireplace for Season Twenty-Eight. However, Moffat was too busy to tackle a two-part story, and he instead agreed to write Blink for later in the year. Instead, Davies offered the job to Doctor Who script editor Helen Raynor, who had been working on the programme since its 2005 return and had already contributed a script entitled Ghost Machine to the first season of the spin-off series Torchwood. She was offered the Dalek adventure around March 2006; her script-editing duties were reduced to give her time to write her screenplay.

Helen Raynor drew inspiration from the Universal Pictures stable of monster movies, such as 1931's Frankenstein

Raynor drew inspiration from the Universal Pictures stable of monster movies, such as 1931's Frankenstein, which were at their zenith during the Great Depression. Similarly, the central role of the Empire State Building -- the world's tallest structure from its completion in 1931 until the construction of the World Trade Center in 1970 -- recalled RKO's 1933 classic King Kong, which culminated in the titular giant ape climbing to the top of the iconic edifice. King Kong also suggested the inclusion of Tallulah and her showgirl act, which Davies felt would add some colour to what might otherwise be a very bleak and sombre story. Raynor was able to draw upon her own experiences for this element of the adventure, having been a theatre director for almost ten years before joining the BBC. She also thought in terms of Gaston Leroux's 1910 novel Le fantôme de l'opéra -- better known to English-speaking audiences as The Phantom Of The Opera -- with the relationship between Tallulah and the mutated Laszlo mirroring that of the musical prodigy Christine and the hideously disfigured Phantom.

Reflecting the major plot points of the narrative, Raynor's scripts came to be called Daleks In Manhattan and Evolution Of The Daleks. Mr Diagoras was named for a Greek poet of the fifth century BC, Diagoras the Atheist, while Tallulah was an homage to the singer played by Jodie Foster in the 1976 children's musical Bugsy Malone. Early on, Raynor set much of the action around the speakeasies which proliferated during the Prohibition era -- the period from 1920 to 1933 when the sale of alcoholic beverages was banned in the United States -- including having Laszlo involved with the mob. However, Davies wanted to avoid the jazz music which would be predominant in such an environment.

The docks were dropped from the story because their distance from the Broadway theatre district made the plot's logistics unnecessarily complicated. Originally, a starting point for the Doctor's investigation was the theft of pigs from ships' cargo, and reports of lights moving under the water which would turn out to be the Daleks. At one point, a major set piece saw Tallulah discover a cage full of the remnants of the Daleks' failed genetic experiments, but this was deemed too expensive to realise. Another significant change involved the climax, in which Laszlo originally perished. Davies asked Raynor to give the character a different fate, as he felt that the tragedy of his death ran counter to the fundamentally optimistic ethos of Doctor Who. Also omitted was a damaged Dalek who had been modified to be steam-powered, since it took the focus away from the genetic manipulations at the heart of the tale.

Daleks In Manhattan / Evolution Of The Daleks was designated Block Four of the Season Twenty-Nine production schedule. Its director would be James Strong, who had handled The Impossible Planet / The Satan Pit the year before; in the interim, he had also made Cyberwoman and They Keep Killing Suzie for Torchwood. No new Dalek casings would be required, since the story involved the same four members of the Cult of Skaro previously introduced in Army Of Ghosts / Doomsday.

James Strong suggested to producer Phil Collinson that a skeleton film crew could fly to New York City to record footage

One of Strong's goals was to achieve a convincing realisation of 1930 New York City. On August 30th, he learned that the behind-the-scenes programme Doctor Who Confidential was planning to fly Raynor to the Big Apple for an on-location interview segment. Strong suggested to Doctor Who producer Phil Collinson that a skeleton film crew could join them to record footage for the Dalek story itself. Collinson indicated his agreement on September 18th. This would be the first overseas shoot for Doctor Who since its revival; most recently, Doctor Who (1996) had been recorded in Canada.

To add to the setting's believability, Strong also sought actors who spoke with a natural American accent. Indeed, previous Doctor Who stories set in the United States, such as 1966's The Gunfighters, had endured criticism for the inauthentic inflections uttered by the guest artistes. Amongst the performers chosen for Daleks In Manhattan / Evolution Of The Daleks was Andrew Garfield, playing Frank. The son of an American father and an English mother, Garfield had moved from his native Los Angeles, California to Epsom, Surrey when he was three years old. Having graduated from the Central School of Speech and Drama in 2004, he had attracted attention for his performance as Romeo opposite Gugu Mbatha-Raw's Juliet in Romeo And Juliet at the Royal Exchange Theatre, Manchester; coincidentally, Mbatha-Raw was playing Martha Jones' sister, Tish, during Season Twenty-Nine. Garfield would go on to become the second big-screen Spider-Man, initially appearing in 2012's The Amazing Spider-Man. He later earned Oscar nominations for Hacksaw Ridge (2016) and tick, tick... BOOM! (2021).

Unaccompanied by any members of the cast, Strong spent October 13th to 15th at locations around New York City, taking plate shots and establishing shots. He visited the Empire State Building on the first day, the Statue of Liberty at Liberty Island and a Fifth Avenue bar called 230 Fifth on the second day, and both the Majestic Theatre and Central Park on the last day. Upon Strong's return to Wales, the production was confined to the studio at Upper Boat for the first few days. From October 23rd to 25th, material in Diagoras' office was recorded; a TARDIS scene, ultimately dropped in editing, was also completed on the latter day. October 26th was the last day of work on the office set, after which Strong filmed the sequences in the lift. He then started work on the action in the sewer tunnels, continuing until the end of the week on the 28th.

After a break on the Sunday, more sewer footage was captured on October 30th, alongside various inserts. From October 31st to November 3rd, the old Nippon Electric Glass site in Cardiff Bay served as the Daleks' transgenic laboratory. During the first day of filming there, it was discovered that the hands had not been ordered for Eric Loren's costume as the hybrid version of Sec. With no time to fabricate replacements, the actor was instead given a pair of black gloves to wear for the sequence in which Diagoras was absorbed by the Dalek. It was then realised that the panic had all been for naught: the hands had been made after all, and the gloves were quietly ignored in subsequent scenes.

Following the weekend, work at NEG resumed on November 6th and 7th. An additional day on the sewer sets at Upper Boat was then scheduled for the 8th. Filming on November 9th began with the materialisation of the TARDIS at the base of the Statue of Liberty; Raynor had originally envisaged the time machine arriving on the roof of a Broadway theatre. Since the budget had not permitted David Tennant and Freema Agyeman to accompany Strong to New York City, this sequence was actually filmed using the back wall of Cogan Primary School in Penarth. The same day, recording of the Hooverville sequences began in Cardiff's Bute Park, and continued on November 10th, 11th, 13th and 14th. The weather was cold and wet, leaving Tennant struggling with his voice as the production shifted to the Parc & Dare Theatre in Treorchy. All of the action around the Laurenzi's stage was recorded there from November 15th to 17th.

The backstage areas of the Laurenzi were actually parts of Headlands School in Penarth, where recording spanned November 20th to 22nd. Part of the latter day was spent at the Cardiff Heliport, where cast and crew remained on the 23rd. A replica of the mast atop the Empire State Building had been constructed there, and Strong also captured shots of the Daleks hovering above Central Park. This marked the end of principal photography for Daleks In Manhattan / Evolution Of The Daleks. All that remained was a shot of a Hooverville guard, filmed at Treberfydd House in Llangors on December 5th, and several inserts, recorded at Upper Boat on December 8th.

Amongst the edits to Daleks In Manhattan / Evolution Of The Daleks was a Central Park sequence excised because it had been shot too late in the day, resulting in insufficient light levels. It saw the Doctor, Martha and Frank returning to the Hooverville with Tallulah in tow, and the Doctor admitting to Tallulah that he would be unable to reverse Laszlo's transformation. When the episodes aired on April 21st and 28th, they occupied earlier time slots than had been the norm at the start of the season: Daleks In Manhattan was scheduled at 6.35pm and Evolution Of The Daleks at 6.45pm. This helped accommodate the addition of a results show, later in the night, which followed up on that evening's broadcast of Any Dream Will Do, the reality competition which Doctor Who preceded.

• Doctor Who Magazine Special Edition #17, 22nd November 2007, “Episodes 4 & 5: Daleks In Manhattan / Evolution Of The Daleks” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who: The Complete History #55, 2015, “Story 182: Daleks In Manhattan / Evolution Of The Daleks”, edited by John Ainsworth, Hachette Partworks Ltd.