The ambitious - but necessary - plan to charge rush-hour drivers has been talked about for years but has been given added impetus by the success of London's Ken-gestion charge.
In yesterday's Observer newspaper, transport secretary Alistair Darling was quoted as being up for a battle with motorists.
Darling told The Observer there could be serious civil liberties implications in monitoring the movements of 24 million drivers nationwide by satellite.
But, he said, the choice was between charging or covering the country with Tarmac.
"You can't build yourself out of the problem that we face," he told The Observer.
"You have a choice in the next 25 to 30 years: either we build more and more motorways - astronomically expensive, environmentally damaging, and I doubt if we could actually do it - or we take a radically different look at how we manage the system. That is where road pricing comes in. I am convinced that unless we look at the possibility of road pricing, then future generations will not forgive us."
Darling will hold a seminar tomorrow with academics, motorists' organisations and others to debate practical issues. He said a nationwide system would be at least a decade away by the time the technology was refined, but added:
"If we don't start thinking about it now, we are going to face a situation where we will have very, very severe traffic problems. We are going to have to face up to these choices and I want to stimulate a proper debate."