Tesla electric cars, marketed as being among the planet’s greenest vehicles, may be behind the production of just as much greenhouse gas as their petrol and diesel equivalents, according to energy analysts.

They have calculated the amount of greenhouse gas generated in building Tesla’s luxury cars and added this to the CO 2 from the power stations that produce electricity to charge them. This was compared with the emissions from making and running normal cars.

“Teslas are not cleaner to run than the average car in the UK,” said Jonathan Harris, of Engaged Tracking, a London-based company that analyses the sustainability and “greenness” of firms for potential investors.