Bosses repeated calls for EU governments to adopt an alternative, cost-effective approach towards reducing emissions.

Sergio Marchionne, Fiat chief executive and president of the European carmakers' association, Acea, said: “The EU objective to bring carbon emissions from cars down to 120 grams per kilometre is achievable through an integrated approach and we fully support that route.”

Manufacturers' preferred approach involves improved car technology, infrastructure changes, a more efficient driving style, CO2-related taxation and the greater use of biofuels. Acea insisted the industry needed sufficient lead-time to prepare for legislation changes and suggested a staggered approach would be ideal. “Sufficient lead-time is indispensable ahead of legislation that is this important. A phase-in could be considered.” The bosses said that a future policy framework should see cars staying accessible to consumers to ensure fleet renewal. They also stressed the effect of legislation "would have to be neutral as far as competition between manufacturers is concerned" and that carmakers should be able to average the CO2 performance of their fleets.