Plans to raise the motorway speed limit to 80mph have been consigned to the slow lane after Transport Secretary Patrick McLoughlin said the move was "not a priority".
The policy was launched with a fanfare in 2011 by then transport secretary Philip Hammond, who claimed the 70mph limit had been "discredited" and a rise to 80mph would boost the economy.
But Mr McLoughlin is reported not to share Mr Hammond's enthusiasm for the plan, which has been condemned by road safety groups.
In an interview with The Times, Mr McLoughlin said: "Look, that's not a priority, to be absolutely honest. You would have to do trials in certain areas so it's not something that's a high priority."
A source close to the Transport Secretary told the newspaper: "This is not going to happen with Patrick McLoughlin as Transport Secretary. Safety is paramount to him and his view of how to run the roads and he would not be confident about how you would do it." The newspaper said Downing Street was understood to be wary of raising the speed limit for fear of alienating women voters.
Mr Hammond announced the plan at the 2011 Tory party conference, saying the 70mph limit had resulted in millions of motorists routinely breaking the law. He said: ''The limit was introduced way back in 1965 - when the typical family car was a Ford Anglia.'" He claimed a rise to 80mph would "restore the legitimacy'' of the system and benefit the economy by ''hundreds of millions of pounds''.
But last year campaign groups estimated that raising the motorway speed limit to 80mph would cost society an extra £1 billion a year, including £766 million in fuel bills and more than £62 million in health costs. The groups, which include road safety charity Brake, the Campaign for Better Transport (CBT) and Greenpeace, also estimated that the higher limit would lead to 25 extra deaths and 100 serious injuries a year, as well as 2.2 million more tonnes of carbon emissions.
Shadow transport secretary Maria Eagle said: "The chaos over plans to change motorway speed limits is extraordinary, even by the Department for Transport's usual standards.
"Only a week after the Roads Minister confidently claimed that trials of a new 80mph speed limit were to go ahead, it's clear that the Secretary of State has applied the brakes on his own reckless policy.
"Labour has consistently warned that a blanket increase in the motorway speed limit risked increasing deaths and serious injuries, pushing up the cost of driving and making it harder to cut the emissions that contribute to climate change."