Most motorheads would look at a car’s spec for its break horse power or torque – but now car buyers can check how green their rides are.

More than 40,000 models have been rated on how many carbon emissions are generated over their lifecycle, from the manufacturing process of the vehicle and the fuel to what comes out of the tailpipe.

The greenest family estate on the new database is a version of the SKODA Fabia Greenline Estate with a Green Car Rating of 27, emitting a total of 2.4 tonnes of carbon per 10,000 miles driven.

The least green estate appears to be a Mercedes-Benz C-Class (G-Tronic) Estate with a rating of 75 and 6.82 tonnes of carbon per 10,000 miles.

The greener estate also seems to work out cheaper to run fuel-wise according to the database, at 7.6pence per mile versus 26.4pence per mile.

The website NextGreenCar.com teamed up with carbon offsetting firm AutoOffsets to compile the huge database.

The Green Car Rating also shows a Climate Change Rating based on the impact of the CO2 from the car and an Air Quality rating.

Omar Soubra, Director at Autoffsets said: “The greenest vehicles still have a carbon footprint, even electric vehicles have a manufacturing footprint and we provide a simple and elegant solution to mitigate these emissions so our customers can drive carbon neutral.”