City Diesel costs 3.5p per litre more than ordinary diesel because it undergoes a more complicated refining process which removes almost all the sulphur and heavy aromatics and reduces particulate emissions by 85%.
BAA currently sells fuel to 23 fleets at Heathrow and buys around six million litres of diesel a year - a third of the 17 million litres used yearly by the 9,000 vehicles based in and around the airport. Head of group motor transport Steve Plent said three more fleet operators had agreed to switch to City Diesel and he had received many more enquiries.
The initiative echoes Sainsbury's subsidy of City Diesel to the general public, who can buy the greener fuel at its 144 supermarket filling stations nationwide. Other fleet operators using the fuel include The Body Shop, Boots, London Underground and many local authorities.