PARENTS using four-wheel-drive vehicles to bully their way through the school-run traffic have been blamed for massive carbon dioxide emissions.

A survey has shown that Sussex drivers with new cars cause pollution levels far higher than the national average due to their love of the gas-guzzling motor.

West Sussex was one of the top ten worst counties for buying gas-guzzling "Chelsea tractors" - so named for the scores of wealthy 4x4 owners who live in that plush part of London.

The figures are part of a nationwide analysis which shows motorists are still buying large numbers of 4X4 vehicles and sports cars despite warnings from environmentalists about the damage to the planet.

Last year the average CO2 emissions for new cars sold in West Sussex was 173.9g/km - 2.7 per cent above the national average - making the county the seventh worst in Britain at buying green cars, opting instead for less fuel efficient cars.

Produced by the Society of Motor Manufacturers and Traders (SMMT), the figures also reveal that the average CO2 emissions for new cars sold in East Sussex was 170.9g/km, which is 0.9 per cent above the national average.

The SMMT compiled the figures by collecting registration data of new sold cars. For each vehicle the SMMT was then able to chart where it was bought and its CO2 emissions, giving an overall average for each county.

Lewes MP Norman Baker said it was very disappointing that Sussex motorists were not doing enough to fly the green flag.

He said: "I suspect these figures are not unconnected to increasing numbers of 4X4s taking children to school or popping down to the supermarket for some guacamole. It reinforces the need to cut the costs of driving green vehicles and increase the costs of driving polluting vehicles."

Lieutenant Colonel Tex Pemberton, West Sussex County Council cabinet member for highways and transport, said a lot of people drove gas-guzzlers around the countryside for sport.

Next month he will launch Pathwatch to urge people to report 4X4 drivers and motorcyclists illegally abusing rights of way following recent Government legislation which reclassifies a number of rural routes as restricted byways.

But he admitted that people would have to change their attitude towards public transport before any dramatic cuts in car pollution could take place.

He said: "There is a real reliance on cars in West Susex because it's a very rural area and some of the public transport arrangements are not as good as we wish. That's not because bus operators won't provide buses in rural areas but due to a tendency for people not to use them.

"If people don't use buses then companies won't provide them. But if operators provide a good service then people might be tempted to leave their gas-guzzlers behind."

Friends of the Earth said the motor industry must be set mandatory targets for producing cleaner cars.

The call is part of the organisation's The Big Ask climate campaign, which would require successive Governments to make annual reductions in CO2.

The national average CO2 emissions for new cars sold last year was 169.4g/km.

This is a long way short of the target set by the European motor industry's trade bodies in the mid-Nineties. Under the voluntary agreement, average emissions should fall to 140 g/km CO2 by 2008.

Friends of the Earth's transport campaigner Tony Bosworth said: "The UK motor industry is failing to take its environmental responsibilities seriously.

"It will almost certainly fall way short of the European car manufacturers' voluntary target for cutting pollution from new cars. This is why mandatory targets for greener cars are needed."

Government efforts to cut down on emissions from traffic have been hampered by opposition to rising petrol taxes and soaring car sales.

Despite changes made in Gordon Brown's budget last month, environmental groups believe the incentives for drivers to buy smaller, more fuel-efficient cars remain insufficient.

The Chancellor cut road tax to zero for the most fuel-efficient cars emitting less than 100 g/km CO2 but no such cars are on sale in the UK. Road tax on new cars emitting more than 225 g/km CO2 was raised to £210 for petrol cars and £215 for diesels.