AFP

Drivers hitting 80mph on the motorway would no longer be breaking the law under plans by the transport secretary to help kick-start the economy.

Philip Hammond has announced that the 70mph limit will be increased to 80mph by 2013, subject to a consultation period of several months.

Mr Hammond said on Thursday that Labour had carried out a “shortsighted and misguided war on the motorist”.

“Britain’s roads should be the arteries of a healthy economy and cars are a vital lifeline for many,” he said. “Now it is time to put Britain back in the fast lane of global economies and look again at the motorway speed limit, which is nearly 50 years old and out of date thanks to huge advances in safety and motoring technology.”

He said that the number of people killed on British roads had fallen by more than 75 per cent since 1965, when the 70mph limit was set.

The decision could aid economic growth because it will allow people to get to meetings faster and cut delivery times, Mr Hammond argues. All ministers are under pressure to come up with ideas to foster economic recovery ahead of a “growth review” to be published in November. Concerns are growing that the economy is flatlining amid wider global financial uncertainty.

Mr Hammond’s proposal was condemned by road safety campaigners and by Greenpeace, which said the move would “raise oil consumption and carbon emissions” at a time of increasing uncertainty in energy supply. Cars use significantly more fuel at higher speeds.

“The government should be looking to reduce the number of deaths and injuries on our roads, not putting forward proposals which are likely to increase them,” said Ellen Booth of the campaign group Brake.

Motoring groups gave a cautious response to the plans. Professor Stephen Glaister, director of the RAC Foundation, said: “Drivers travelling that 10mph quicker might reach their destination sooner, but will use about 20% more fuel and emit 20% more CO2. There is also likely to be a slight increase in road casualties. And what about enforcement? If police follow existing guidelines, many people could do 90mph before action is taken.

“Before you change a speed limit, you have to know whether you are doing it for safety, economic or environmental reasons. Unfortunately not all of these are compatible.”

Supporters of changing the limit, however, argue that the number of driving fatalities on motorways is a small fraction of the total, at 132 out of 2,222 in 2009.

Research from the transport department suggests nearly half of cars exceeded the 70mph limit on motorways last year – with very few being prosecuted. Campaigners fear, however, that raising the limit to 80mph could lead to people driving even faster than at present.

Mr Hammond will argue that the economic impact of raising the limit should be set against other issues such as safety. He will demand a “rigorous cost benefit analysis of speed limits” to weigh these factors against each other.

The speed limit of 60mph on motorways for larger lorries above 7.5 tonnes will remain in force.

The British limit of 70mph is lower than that in many other European countries. The limit in Ireland and Spain is 75mph while it is 81mph in France and Italy. Speed limits in the US vary from state to state and are typically between 55mph and 70mph.