The speed limit on Britain's motorways is to rise to 80mph, but with a big expansion in the number of 20mph zones in cities and towns, i has learnt.
The Government's intention to bring in the new speed limit will be announced at the Conservative Conference next week by the Transport Secretary, Philip Hammond, as part of a deal negotiated with the Liberal Democrats.
Ministers will consult on the proposal later in the year along with plans to expand significantly the number of areas covered by a 20mph limit.
Mr Hammond argues that the new 80mph limit will shorten journey times and help boost the economy. But the move will be criticised by environmentalists who point out that cars use about 20 per cent more fuel at the higher speed. Road safety campaigners condemn the proposals, saying it will lead to an increase in deaths.
Police currently turn a blind eye to most motorists who drive at 80mph, and they are rarely prosecuted. There are concerns though that if the change goes ahead, 90mph could become the new 80mph. As part of the deal, the police will be expected to enforce the new speed limit more rigorously.
A source close to the negotiations said: "The Tories wanted to announce the 80mph limit next week because it appeals to their base and they can sell it as promoting business. Meanwhile the Liberal Democrats claim there is strong evidence that, in road safety terms, increasing 20mph zones saves lives. A deal has now been done and will all go into one consultation paper."
Mr Hammond has made clear his concern that campaigners have for too long used road safety as an excuse to prevent the motorway speed limit being raised. He believes that the economic impact must also be taken into account.