A number of popular plug-in hybrid electric vehicles (PHEVs) have been found emit significantly more carbon dioxide than official measures suggest.
The research by Austria’s Graz University of Technology found that BMW’s 3 Series emitted 112g of carbon dioxide per kilometre, three times its official rating of 36g.
Peugeot’s 308 polluted 20 per cent more than its official rating of 27g, while Renault’s Megane was 70 per cent above the official test of 30g.
A BMW spokesperson said: “On-the-road driving presents infinite variability of multiple criteria and so it is not surprising that there are some differences to the WLTP figures.”
Campaign group Transport and Environment said the tests showed governments should focus on incentivising the purchase of fully electric vehicles rather than hybrids.
Anna Krajinska, vehicle emissions manager at Transport and Environment, said: “Plug-in hybrids are sold as the perfect combination of a battery for all your local needs and an engine for long distances.
“But real-world testing shows this is a myth.
“In city tests, just one of the PHEVs has the electric range advertised, while all three emit more than claimed in commuter driving.
“Lawmakers should treat PHEVs based on their actual emissions.”