In its latest study, the sustainable transport group said petrol attracts on average 14 cents more tax per litre than diesel, indirectly subsidising diesel cars to the order of around €2,600 over their lifetime.

This equates to a 30% discount per unit of energy compared to petrol. The study noted that the price differentiation varies between markets – the UK already having per-litre tax parity for the two fuels, compared to a 28 cent advantage in The Netherlands. As a litre of diesel contains more energy than a litre of petrol, this equates to between a 10% and 44% advantage per unit of energy for diesel vehicles.

Transport and Environment said this has led to larger vehicles being used, as well as increasing mobility and boosting sales of diesel engines. The group added that nine out of ten diesel cars fail to meet NOx limits when driven on the road according to its ‘Don’t Breathe Here’ report, published in September.

Carlos Calvo Ambel, policy analyst at T&E, said: “The recent diesel air pollution scandal highlights again why Europe should end its diesel subsidy that now amounts to €2,600 per car. With oil prices low, now is the time to act and finally align petrol and diesel taxes.”