During late 1968, Gerry and Sylvia Anderson collaborated with producer
Reg Hill and writers
Donald James and
Tony Barwick to develop the format for the series and the first episode, "Identified". Initially, Earth's defence organisation was to be called UFoeDO – Unidentified Foe Defence Organisation – which was not a secret operation like SHADO was to become. The commander of UFoeDO was to be a Commander Straeker — later shortened to Straker — with
Ed Bishop cast in the role. Second in command was to be Alex (later renamed Alec) Freeman, played by George Sewell. Both Bishop and Sewell had appeared in the Andersons' film
Doppelgänger. Initially the Moonbase Commander, named Franco Desica, was to be played by Italian actor
Franco De Rosa. De Rosa was later fired after three days of filming for causing considerable delays. De Rosa's character was dropped entirely from the show. Some of Desica's dialogue was repurposed for a new Moonbase commander, Lieutenant Gay Ellis (played by
Gabrielle Drake) (this character was initially called Lieutenant Paula Harris). The captain of the
Skydiver craft, cast as Jon Karlin, was to be Jon Kelley, but before filming commenced the part was restructured and offered to dancer
Peter Gordeno, and the character renamed Peter Carlin. Kelley was re-cast as
Skydiver navigator John Masters. Towards the end of April 1969, after five months of pre-production, principal photography for the pilot episode began with Gerry Anderson directing at
MGM-British Studios in Borehamwood. Second unit filming took place at
Burnham Beeches in Buckinghamshire; this included the UFO attack on Straker and Henderson's Rolls-Royce. This unit also filmed the scene with Carlinand his sister Leila (Edwina Carroll) when they discover a UFO landed in a wood; this was filmed at
Black Park at
Iver Heath, close to
Pinewood Studios. Additional location shooting included
Neptune House at
ATV Elstree Studios. This building was used as the administration block for Harlington-Straker Studios. Various SHADO members were filmed arriving at this building. Other locations used for the filming included Handley Page Ltd,
Radlett Aerodrome, Hertfordshire. In the episode, Colonel Lake holds a newspaper with the date of 24 August 1980; this details the exact date that SHADO became operational. ==Broadcast==