MINISTERS have been accused of betraying motorists by considering a scrappage scheme for only 9,000 diesel cars.
The Government also said it would consider slashing the motorway speed limit from 70mph to 60mph as it finally revealed how it plans to tackle toxic emissions.
The measure was buried in a 252-page official report that also proposed scrapping 6,000 of the most toxic petrol vehicles.
Drivers would be paid up to £8,000 to trade in the diesel and petrol cars and replace them with electric versions, at a cost of around £110million.
But last night Fair- FuelUK founder Howard Cox blasted the plans.
He accused the Government of “betraying hard-working families, white van drivers and small businesses”.
And he said the scrappage schemes would only benefit “half a per cent of the dirty diesels”.
Around two million vehicles are thought to be affected by the Government’s clean air drive.
But the Department for Environment, Food and Rural Affairs report ruled out scrapping all diesels except those with the cleanest engines as that would cost £60billion.
Councils could also be asked to change junctions and remove traffic calming measures before they can tax diesel drivers.
Environmental campaigners accused the Government of “tinkering at the edge” of the toxic pollution problem, which is linked to 40,000 premature deaths a year.
London Mayor Sadiq Khan called it a “weak plan” that “lacks urgency”.
Senior Tories said the plans were in consultation and could change.
A SPEED limit of 60mph could be introduced on motorways under plans to cut air pollution.
The proposals come amid fears that cars release more toxic fumes when travelling at speed.
Limits on highways with the worst emissions could be cut by 10mph.
Ministers have asked Highways England to carry out further research on the proposals.