Aside from their luxurious appearance and relative rarity, one of the main selling points of Tesla electric cars is that their production results in less greenhouse gases than regular petrol-driven cars.

But a team of UK-based analysts have suggested the Tesla Model S is as bad for the environment as its combustion engine counterparts.

The problem, say the analysts, is that the energy needed to charge a Tesla battery comes largely from power stations. In the UK, half of our power comes from gas and coal.

The study was carried out by London-based Engaged Tracking, a company that scrutinises the green credentials of firms for would-be investors.

However, their research was roundly disputed by Tesla.     

In the US, previous research gave the impression Tesla's cars were more environmentally friendly than regular cars - but only when the vehicles entire life-cycle was taken into account.

Engaged Tracking estimated the amount of greenhouse gases emitted in the production and ongoing running of a Tesla Model S.

Speaking to the Sunday Times, chief analyst Jonathan Harris said: 'Teslas are not cleaner to run than the average car in the UK. The annual emissions of a UK car is 1.5 tons of carbon dioxide, based on an average of 7,800 miles a year.

'Both the Tesla Model S vehicles we analysed have the same emissions as an ordinary petrol car of 1.5 tons of CO2 per year.'

Harris went on to say that the comparatively smaller BMW i3 electric was actually greener than the Tesla - to the tune of 15 per cent.

However, Tesla took issue with the fact that two cars of significantly different size were compared - suggesting it was unfair.

Instead, Tesla, run by billionaire Elon Musk, compared the Model S to a petrol-driven car of similar size - the Mercedes S-Class. The Mercedes produced 300 per cent more emissions, according to Musk's firm.

A spokesman said: 'The Engaged Tracking data has been cherry-picked, and is not a valid analysis to demonstrate the cleanliness and efficiency of the Model S.

'It makes no sense to compare Model S to the average annual emissions figure for cars in the UK, because that average includes a lot of smaller models that are dissimilar to Model S.

'Any fair analysis shows that electric vehicles like Model S and Model 3 generate far less CO2 per mile than any comparable gas-powered car.'