Owners of the biggest gas-guzzlers would see the cost of an inner zone permit double from the current £160 a year to £320.

But drivers of the least polluting vehicles in the outer zones could see their charge fall from the current £80 to just £15.

And residents would also face higher charges for second vehicles.

The proposals, due to be discussed by councillors next week, are intended to encourage people to switch to greener cars.

Robert Aldridge, environment leader in the Capital's Liberal Democrat-SNP administration, said it was reasonable that motorists with 4x4s and other large polluting cars should pay more.

He said several key locations in the city were showing cause for concern in terms of CO2 levels.

He added: "There is a national acceptance that more needs to be done to influence the vehicle choices that people make. If this is to happen, then local authorities need to play their part and take action to bring about local change."

The council insisted the proposals – which will cost £50,000 to implement and are unlikely to be introduced for at least two years – were not a money-making exercise and claimed only 20 per cent would pay more while two-thirds of people would see their charges go down.

But there were warnings from opposition politicians and motoring organisations that the proposed changes did not address the main cause of pollution and could prove unfair to families and disabled people.

Andrew Burns, leader of the council's Labour opposition, said there should be extensive public consultation before any such scheme was introduced.

He said: "The principle is potentially worth looking at, but unfortunately there has been no consultation with anyone outside the current administration."

Sheila Ranger of the RAC Foundation warned such charges could be unfair on people with large families and disabled people.

She said: "Not everyone who drives a large car has a big salary. Some people have big cars because they have three children and they need room for child seats.

"A scheme which insists everyone with a larger, less efficient car should pay more penalises larger families."

Ms Ranger also questioned the logic of using higher parking charges as a way to cut carbon emissions.

"A car that's parked isn't causing any pollution so using these charges to try to cut emissions doesn't make a lot of sense."

She said if the council had given a few years' notice of the change, drivers could have taken it into account when buying their next car. "As it is, people are going to be penalised for the cars they already own," she added.

Mark McInnes, Tory transport spokesman on the council, said motorists were always suspicious about new charges.

"It has to be about providing incentives for the future, not penalising people for decisions already made."

And Bruce Young, Lothian and Borders co-ordinator of the Association of British Drivers, dismissed the proposals as a "political exercise" intended to make life difficult for motorists.

He said: "I think drivers will prefer to have a new council than a new car."