While exploring an abandoned house, Sally Sparrow discovers a message left for her, concealed behind wallpaper, in 1969 -- a message left by a mysterious figure called “the Doctor”. What starts off as an intriguing puzzle suddenly becomes deadly serious when one of Sally's friends disappears in the house, cast backward in time to 1920. Key to these events are four statues which seem to move of their own accord... but what are the Weeping Angels?

With The Empty Child / The Doctor Dances and The Girl In The Fireplace, Steven Moffat had contributed two of the best-received stories to the new Doctor Who series' first two seasons. Executive producer Russell T Davies was eager to get Moffat on board for the 2007 schedule as well, but Moffat was much busier this time round, as he was serving as writer and executive producer for the six-episode Jekyll. Davies originally hoped that Moffat would write the season's two-part Dalek story (which ultimately became Helen Raynor's Daleks In Manhattan / Evolution Of The Daleks), but the author's schedule would not permit it. Davies then suggested developing another two-part idea Moffat had proposed for the 2005 season, but again, Moffat was forced to decline. After next turning down a single-episode story to run early in the year, a recalcitrant Moffat finally offered to tackle the late-season “Doctor lite” adventure around March 2006.

The addition of a Christmas special to the Doctor Who production slate had forced the production team to “double-bank” episodes once per year, which meant that a single-episode story would be made at the same time as a two-part tale. Of necessity, then, the former could only feature the Doctor and his companion in minor roles. For the 2006 season, Love & Monsters had fulfilled this “Doctor-lite” function (being made alongside The Impossible Planet / The Satan Pit), while Moffat's episode would be double-banked with the preceding story, Human Nature / The Family Of Blood.

To help speed things along, Moffat decided to base his script upon a short story he had written for the Doctor Who Annual 2006, published by Panini Books in August 2005. Entitled “What I Did On My Christmas Holidays by Sally Sparrow”, this concerned a twelve year-old girl who discovers messages addressed to her behind wallpaper, in photographs, and on a videocassette. These have all been left by the Doctor, who is stranded in 1985 because the TARDIS has “hiccoughed” twenty years into the future. He needs Sally to pilot the time machine back to him. Since this plotline already marginalised the Doctor's presence, Moffat began work on an expanded version, called “Sally Sparrow And The Weeping Angels”.

Reasoning that children preferred to watch protagonists older than themselves, Moffat decided to make the screen version of Sally an adult. He created the Weeping Angels to serve as an antagonist -- which his original short story lacked -- and deposited the Doctor and Martha in 1969 so that the appearance of the aged Billy would be more dramatic. At one point, Sally would have been seen to be pregnant at the episode's conclusion, but Moffat decided that it was more effective to delay Sally and Larry's romance until after her meeting with the Doctor.

“Sally Sparrow And The Weeping Angels” was originally intended to form the sixth production block of the season, but when it was decided to move up the recording dates, it became Block Five. The director was Hettie MacDonald, whose credits included the feature film Beautiful Thing as well as episodes of Poirot, Servants and Casualty. Around the time that production began, Moffat decided to give the adventure its final title of Blink, although at Davies' encouragement, this meant that he then had to trawl through his script in order to insert as many references to the word as he was able.

The first shot completed for Blink was the Doctor's hologram, performed on the TARDIS set at Upper Boat Studios on November 7th. The main stretch of recording began on November 20th. On this day, the old National Westminster Bank was the police station, while the street scenes were filmed at West Bute Dock (as well as pub footage which would later be edited out of the episode). Both were in Cardiff Bay, as was the Coal Exchange where scenes in the police garage were taped on the 21st, alongside the DVD easter eggs. On the 22nd, the material in Billy's hospital room was taped at the Caerphilly Miners' Hospital.

MacDonald's team was fortunate to locate a ramshackle old house on Field Park Road in Newport which could serve as Wester Drumlins. Three days were spent there, from November 23rd to 25th, although the edifice's derelict state made the experience at times uncomfortable. The 27th started with the cafe sequence at Oddverse Cafe in Newport, then shifted to Diverse Vinyl, which posed as Banto's DVD Store. The shop was redressed the next day to reflect its transformation into Sparrow & Nightingale; Billy's arrival in 1969 was then filmed, at Newport's Charterist Tower. On November 29th, the graveyard scene was recorded at St Woolos Cemetery in Newport before cast and crew moved back to the house on Field Park Road, where work continued to the next day.

December dawned with the material at Kathy's apartment, filmed at a residence on Llanfair Road in Pontcanna. MacDonald's team then returned to Upper Boat for the sequence of Sally and Larry inside the TARDIS. Work there continued to the 2nd, which saw the recording of the scenes in the cellar of Wester Drumlins. On Decemer 9th, Kathy's appearance in 1920 was completed at Cwm Ifor Farm near Caerphilly. Finally, MacDonald recorded various inserts at Upper Boat on January 9th, 2007.

One humorous sequence edited out of Blink would have formed part of the pre-credits teaser. After Sally discovered the message behind the wallpaper, Moffat had requested the sound of cliched horror movie music. This would turn out to be Sally's mobile phone ringtone, and it was actually Kathy calling her friend from a pub. Also cut was Larry's admission in the epilogue that he regularly checks to ensure that the Weeping Angels are still petrified.

• Outpost Gallifrey: New Doctor Who Series News Page, edited by Shaun Lyon.
• Doctor Who Magazine Special Edition #17, 22nd November 2007, “Episode 10: Blink” by Andrew Pixley, Panini Publishing Ltd.