Manufacturers may be forced to increase prices in order to fund development of more environmentally friendly vehicles.

An environmental report has shown a number of carmakers must make extensive changes to their models to comply with 2015 European Union CO2 emission standards.

Europe’s Transport and Environment (T&E) group has released statistics showing Mazda faces a significant investment bill – potentially forcing up prices.

The EU report said: “It needs to improve the emissions of its models by 21% to reach the 2015 mandatory target of 130g/km average for all cars made by a manufacturer in Europe.”

Suzuki has an even great challenge, needing to make 22% of improvements by 2015.

The report noted PSA Peugeot-Citroën is “the best-placed carmaker” – only 8% away from its target.