Last year saw the greatest single-year decline in average CO2, which the analyst said was due to the rich mix of customer demand for more fuel-efficient vehicles, the introduction of CO2-based taxes in some markets and national scrappage schemes across Europe favouring smaller, cleaner cars.

The volume-weighted European new car average is now 145.9g/km, almost 20g/km less than 2003, when JATO began collating European CO2 emissions data. Half of all new cars sold in the 21 countries analysed had official CO2 emissions of 140g/km or less, compared to only 23% in 2003.

David Di Girolamo, head of JATO Consult, said: 'The pace of improvement is remarkable and shows just how rapidly the industry has reacted to environmental demands. In 2003, only 24% of the market achieved an average of 130g/km. This was 40% by 2007, 51% in 2008 and 69% last year, already ahead of the 2012 EU target. This achievement is even greater when set in the context of new cars becoming larger, safer and better equipped, as consumer demands reach ever higher.'