Prime Minister Winston Churchill summons the Doctor and Amy to Blitz-torn London. The British forces are at their lowest ebb, but a scientist named Bracewell has come to Churchill with an amazing invention -- powerful miniature tanks he calls “Ironsides”. The Doctor, however, recognises the Ironsides for what they really are: the Daleks. With a Nazi bombing run closing in, and Churchill convinced of the Ironsides' benevolence, the Doctor must learn Bracewell's secret and uncover the Daleks' plans.

In planning the early stages of Doctor Who's thirty-first season, executive producer Steven Moffat decided to hew closely to the format established by his predecessor, Russell T Davies. Davies had always included a trip to Earth's past amongst the early stories of each season, with the Doctor often encountering a famous historical figure. The first example of this had been Mark Gatiss' The Unquiet Dead, which had paired the Ninth Doctor with Charles Dickens. Moffat sought to put a new spin on this approach with a story that featured both British Prime Minister Winston Churchill and the Daleks, set during the London Blitz. This was inspired by a visit he made with his sons, Joshua and Louis, to the Cabinet War Rooms which had been Churchill's base of operations during World War II and were now a museum. For added variety, he decided that Churchill and the Doctor should already be old friends.

To write the adventure, Moffat approached Gatiss, with whom he was also working on Sherlock, a modern-day version of Arthur Conan Doyle's Sherlock Holmes mysteries. Gatiss' last broadcast Doctor Who script had been The Idiot's Lantern in 2006, but he had also written “The Suicide Exhibition”, a Blitz-set adventure which had been under consideration for Season Thirty before being displaced by The Fires Of Pompeii. Gatiss accepted Moffat's offer to contribute to Season Thirty-One around September 2008. He was keen to write a Dalek story against the backdrop of the Second World War, given that the Nazis had been one of Terry Nation's chief inspirations during his creation of the Daleks in 1963.

For the tone of his script, Gatiss looked to classic British war movies such as 1968's Where Eagles Dare (from which he borrowed the call signs used in the episode). He also wanted to emphasise the deviousness and manipulativeness of the Daleks, characteristics which had been especially prominent in his favourite Dalek story, 1966's The Power Of The Daleks. He decided to use that adventure's basic notion of the Daleks masquerading as factotums for a group of humans, and had the Daleks utter the line “I am your soldier” in homage to the earlier story's eerie “I am your servant”.

Perhaps the most significant decision made by Moffat and Gatiss was to use this story as a vehicle to redesign the Daleks. When Doctor Who had returned in 2005, the appearance of the Daleks had remained very faithful to that seen in the original series. With so many of the visual elements of the show changing to herald the start of the Matt Smith era, Moffat felt that this presented an excellent opportunity to update the Daleks as well. He wanted them to be bigger and more menacing, but also more colourful. In particular, he and Gatiss both thought in terms of the Doctor Who feature films from the mid-Sixties, which had starred Peter Cushing as “Dr Who” and had featured towering Daleks in a variety of Technicolor liveries. They decided to introduce five different types of Daleks, each serving a different function. Gatiss named the white Supreme, the red Drone, the orange Scientist and the blue Strategist; Moffat contributed the yellow Eternal (although he had no particular plans for what this enigmatic title might signify). Black and green Daleks were also considered but rejected. Gatiss' story would culminate with the introduction of this new “Dalek Paradigm”, inspiring the title Victory Of The Daleks.

The task of redesigning the Daleks fell to production designer Edward Thomas, working with concept artist Peter McKinstry. The pair conceived some very radical departures from the traditional Dalek image, but Moffat encouraged them to retain the basic silhouette and the traditional Daleks elements. Ultimately, the most significant changes included a sharp-edged head grille and a bulkier rear skirt section which Thomas conceived as storing various weapons which could be rotated onto the front of the Dalek. At Moffat's suggestion, the Dalek eyepiece was given an organic eye to remind viewers of the living creature housed in the Dalek shell. Whereas the earlier twenty-first-century Daleks had been sized so that the eyestalk would be level with the eyeline of the diminutive Billie Piper (who had played Rose Tyler), the new Daleks were proportioned relative to the much taller Matt Smith and Karen Gillan.

Victory Of The Daleks would form part of Season Thirty-One's second recording block alongside The Beast Below, directed by Andrew Gunn. It was originally planned to construct the War Rooms as a studio set, but the production team was able to secure permission to use the bunker of the Joint Resilience Unit in Swansea, which had been an actual Ministry of Defence command centre during the 1950s. Work there began on August 21st, 2009 and then continued from the 24th to the 26th, covering scenes in the Map Room and Churchill's office.

On August 27th, Bracewell's rooftop demonstration of his Ironsides was filmed at the Glenmorgan Building in Cardiff. Material in Bracewell's lab and the lift was recorded on the 28th and 29th at Jacobs Market in Cardiff. This included a new final sequence involving the Doctor, Amy and Bracewell. Originally, the episode would have concluded with the time travellers watching Bracewell enter the post office about which he had reminisced, and the crack in time would have been revealed on the wall of a nearby cottage in front of which the TARDIS had materialised.

Gunn's team next spent two days at Brackla Bunkers in Bridgend, on August 31st and September 1st, taping scenes in the storage area and various corridors. The final location used for Victory Of The Daleks was the humidifier area of Freeman's Cigar Factory in Penarth, a huge steel-walled space which served as the interior of the Dalek saucer. Work there took place from September 2nd to 4th, and saw the introduction of the five new Dalek casings. This left only material to be filmed at Upper Boat Studios, with the TARDIS set in use on September 8th and the Spitfire effects sequences completed on the 23rd. The voice of the Spitfire pilot was provided by Gatiss himself.

• Doctor Who News.
• Doctor Who Magazine Special Edition #26, 30th December 2010, “Victory Of The Daleks” by Andrew Pixley, Panini Publishing Ltd.