Future plans for tolls on Britain's roads will include all roads, not just the busiest, it has been reported.
Tolls and congestion charging arouse strong feelings
It had been suggested earlier that an in-car satellite tracking system could bill drivers for school runs and travelling on motorways at rush hour.
But a government adviser quoted in the Sunday Mirror said there would be variable charging on all roads.
The newspaper said charges could be offset by reductions in road tax and petrol duty.
Professor David Begg was told by Transport Secretary Alistair Darling to lead a committee to establish how a national congestion charging scheme would work.
The Mirror said the cost of travelling would be as low as 1.6p a mile in quiet rural areas to 16p on the most expensive routes. The scheme would require expensive satellite-tracking equipment to be fitted in all cars.
Professor Begg said: "It is now a matter of when, not if. Six months ago it was on the shelf, but Mr Darling is now very serious about it.
"The government has realised that there is only one way to reduce congestion
and that does not mean trying to build a way out of it."
The government-appointed committee, which includes industry representatives, is
due to report back next year.
Professor Begg said the scheme could reduce congestion by 30%
and pollution by 40%.
The first toll motorway, part of the M6, opened this week, but had been billed as a one-off.
In June, Mr Darling said a national toll scheme based on satellite tracking could be a decade away, although lorries will be monitored under the scheme from 2006.
His proposals to charge school run parents and motorway users at peak times were criticised by motoring groups.
They said motorists would only accept new charges that were "revenue neutral", with the government reducing other charges correspondingly so that no extra money was made.
Last year, the government predicted traffic jams could increase by up to a fifth by the end of the decade.
The success of the congestion charge in reducing traffic in London has led to some commentators saying it is inevitable that some form of charging will be introduced nationwide.
Edmund King, of the RAC, said charges on every road were neither acceptable
nor practical, but that with proper safeguards, charges on the busiest 10% of roads would be welcome.
The AA Motoring Trust warned satellite tracking was the most unpopular form of
Spokesman Paul Watters said: "They don't like it because they don't think it will work, they don't like the infringement of their liberties and they think it will cost a fortune to set
"People can understand city charging like in London. They can understand
French motorways, where you pay for a premium service. They can probably get to
understand the M6 Toll.
"But tracking is too Big Brother. There is a lot of work to be done before
people are convinced."