After rudimentary purification and regeneration of the biocatalysts, the CO2 is transferred to a Biocatalytic Reactor Matrix where mass quantities of biocatalysts function in a matrix of liquid reaction chambers breaking down CO2 and turning it into hydrocarbons.

CNN: Turning carbon dioxide into fuel

This reaction is put down to the ground-breaking special effects which gave the film an unprecedented air of reality.

BBC: TV premiere for The Exorcist

The move provoked an angry reaction from the French government, which accused Arcelor Mittal of breaking a 2006 commitment to keep the blast furnaces running - a claim denied by the steel giant - and criticised the firm for refusing to sell off the site as a whole.

BBC: SOS sign at Arcelor Mittal's steel plant