The scheme will be unveiled this Wednesday by Alistair Darling, the Secretary of State for Transport, in an attempt to persuade car buyers to switch to more fuel-efficient models.
The new labels, which will be introduced in showrooms and on websites later this year, will be graded from deep green for very clean and fuel efficient through to deep red for polluting and fuel-hungry.
The label will also show motorists how much vehicle excise duty the car will attract.
Mr Darling said: "The labels will send a clear message to motorists that they can make a real difference by choosing clean, fuel-efficient cars."
The measure follows growing evidence that the Government's previous attempts to persuade motorists to buy cleaner cars by imposing higher duties on fuel-hungry vehicles are failing. In 2003, motorists bought cars that were less fuel efficient than in 2002, despite warnings and a pounds 95 duty on the largest cars.
Experts believe the Government's attempts to achieve deep cuts in carbon emissions from cars are floundering because the British are keen on high- status off-road "sports utility vehicles", such as the Land Rover Discovery and Toyota Landcruiser, or larger-engined saloons.
The new labels are based on the successful A to G energy-labelling scheme already used on fridges, freezers and washing machines. Now nearly all kitchen appliances carry the top A or B ratings.
Ministers hope car makers, who sell 2.6 million new cars every year, will start using energy labels to market their cars in the same way manufacturers such as Renault boast that their cars carry the safest five-star safety ratings. Already, What Car magazine has agreed to promote the new scheme.
The measure has been introduced despite concerted opposition from car makers.
Tim Brown, deputy secretary of the National Society for Clean Air and one of the scheme's architects, said: "Most big cars will have F labels, so the pressure will be on the car industry to move up the scale. People will have no excuse for buying gas-guzzlers."
In a further move to boost the sale of more efficient cars, ministers will announce within weeks a new programme to give grants worth up to pounds 1,000 to ultra-clean and ultra-fuel-efficient cars.Reuse content