Two former EU commissioners have denied any knowledge about the possible use of defeat devices by the car industry.

Antonio Tajani and Janez Potočnik, who served respectively as the commissioners for industry and environment from 2010 to 2014, faced questions from a European parliament committee which is investigating the “dieselgate” scandal.

It comes as Volkswagen was found to have been cheating on its emissions tests.

Mr Potočnik told MEPs he had raised questions about the big gap between car emissions measured during lab tests and on the road as long ago as 2011 but had never been aware of manufacturers cheating.

Mr Tajani added during his mandate he had never received any information from anybody on possible emission test “defeat devices” in cars.

He also denied covering up the results of Joint Research Centre tests showing which models were high polluters, noting the survey had been done on a small sample and the findings had to be rendered anonymous.

The Committee of Inquiry into Emission Measurements in the Automotive Sector said it will continue questioning different commissioners on the case.