Germany's three biggest carmakers have criticised a planned European Union target to cut car exhaust emissions as "unrealistic" and "technically unrealisable" and warned that it could make swathes of the European industry unviable.

The chief executives of Volkswagen, Daimler-Chrysler and BMW described the EU's proposed carbon dioxide emissions target as "a massive industrial policy intervention that will burden the entire European automobile industry, but the German [industry] in particular" in a letter to European Commission officials seen by the Financial Times.