BT's broadband internet access campaign is firmly in the "blockbuster" category, according to St Luke's creative directors and the authors of the scripts, Al Young and Julian Vizard. They claim it's the biggest project they've ever been involved in.
Their colleagues at the production company Hammer & Tongs, the post-production company The Mill, the special effects shop Asylum, the sound specialist Wave and the music agency Soundtree agree with Young and Vizard.
"When we first read the script, we thought 'this is huge'," H&T's producer, Nick Goldsmith, recalls. "It had everything you could possibly ever dream of in an ad - fantastic visuals, a compelling message and lots of human involvement," he adds.
The head of TV at St Luke's, Kate Male, says the director, Garth Jennings, was chosen because of his ability to make the human angle the most important element of the ad.
BT approved the script in mid-January, and by the end of the month, Jennings had done the first "treatment". The Mill was briefed on the character creation, the dragon, the rhino and the WW2 fighter plane among others.
At the same time, Aardman Animations entered the fray with its claymation pig models, and Asylum started work on constructing a 1.5 tonne steel rhino, working out the technicalities of creating a windswept market street for the plane scene and testing the collapse capabilities of Vitara Jeeps.
Male says just the logistical aspect of dove-tailing the activities of several different contributor companies made the project the biggest St Luke's has handled. She cites the scene in London's Victoria Station, in which "Dave" calms two fighting computer-game characters, as a tricky example during the 12-day shoot in April.
"We had a restricted shooting time, and had to choreograph his interaction with the characters, who obviously weren't there. We used poles as spotters, and planted extras in the existing crowds to respond to the movement," she says.
A team from The Mill played a major role during the shoot, helping pre-visualise the computer-generated overlay they would create.
Asylum's senior SFX technician Mark Mason agrees with Male. "It was all testing stuff - the market scene involved air rams to tip up the stalls, behind which were air mortars loaded with produce. The debris, which poured down the street, was controlled by four air movers, and the whole thing was controlled by computer to ensure it all worked in sequence. We needed four takes, which meant it all had to be cleaned up between each. On top of that, we had 100 extras to keep safe. It was a long day," he recalls.
Once the finished edit had been decided, The Mill's team of software experts were able to use their existing work and plans to build the rest of the computer-generated parts of the film.
The 100-storey dragon's docile temperament was captured, along with the rumbustious rhino storming down the Surrey high street, by a wide range of CG programmes, according to the 3D producer Simon Venning. The specially composed music was also tailored to fit the action during the post-production period.
Vizard and Young are thrilled with the results: "It was important to have the action happening on a very British street - it's Hollywood meets suburbia."