Wizardry transformed a pastoral idyll into pandemonium

It was the centrepiece of Danny Boyle's opening ceremony for the London 2102 Olympic Games, leaving viewers gasping with admiration.

The 80,000 spectators left the stadium wondering exactly how Boyle and his team had achieved the incredible transformation of the green and pleasant land that opened the ceremony into a smoke and flame-filled vision of industrial Britain in 14 minutes. More than a billion television viewers around the world asked themselves the same question.

Now the man asked by Boyle to turn that vision into reality discloses the secrets behind the stunning sequence. Piers Shepperd, Danny Boyle's technical director for the opening ceremony, and the man who masterminded the complex scene change, explains how:

?Banks of fans were used to blow up the 100ft chimneys like bouncy castles;

?The life-size steam engines were constructed on stage by teams of stage hands who were among 1,000 performers in the stadium;

?Special lighting and fireworks effects created the river of molten steel used to "forge" the central Olympic ring;

?A series of winches raised the ring to join with four others "flying" in on cables;

?A shower of sparks was made to erupt from the rings.

Shepperd began designing the sequence in October, working hand-in-hand with the stadium designers whose infrastructure, particularly the network of steel cables in the roof, was crucial to its implementation.

Gathering a small team of technicians and designers, all sworn to secrecy, Shepperd began the process of planning in minute detail how to dismantle the bucolic stage setting and replace it with factories and mills. Boyle called the 15-minute sequence Pandemonium, but there could be no hint of chaos on the stage.

Each movement, from the removal of thousands of square feet of turf to the erection of seven giant chimneys, had to be planned to the last inch and cued with precision.

Shepperd was associate technical director at the opening and closing ceremonies in Athens in 2004, and at the Doha Asian Games in 2006, where he used many of the same crew.

The 41 year-old said: "Technically it was as complex as anything seen at Sydney, Athens or Beijing, but the fact that everyone involved in putting it together was based in the UK made the job so much easier.

"We are all totally thrilled with the end result because it's totally unique."

Boyle told his performers "you are creating Hell". But he also emphasised that the Industrial Revolution was a key moment in history, giving birth to democratic movements, such as that of the Suffragettes and the demand for universal health care.

He told them: "It was monstrous but it changed lives. People, including myself, can read and write thanks to it. The workers of the Industrial Revolution built the cities that are now the settings for every Games."

Dave Nattriss, 33, a freelance web designer, played one of the factory workers, also helping to change the scenery. He said: "We all had little FM radios with earpieces. At one point there was an instruction, 'If you see any of your friends on fire, just wipe it off and carry on'."

The sequence was greeted enthusiastically, and was recognised as central to Boyle's ambition of explaining to the world where Britain came from and who we now think we are.

Frank McDonough, professor of history at Liverpool John Moores University, said the ceremony "reflected the impact of Britain on history and culture in a quirky and stunningly inventive manner".