Energy company E.ON UK, will now only order new company vehicles with a CO2 rating of 165g/km or less.

Derek Parkin, managing director of business services, said: "Tackling climate change is at the heart of everything we do, from reducing the emissions of our power stations to such measures as this decision on company cars.”

E.ON believes the move will reduce average emission levels across its company car fleet to 140kg/km, a reduction of over 12%.