The speed limit on Britain's motorways is set to be increased to 80 miles per hour (mph).
Transport secretary Philip Hammond is due to make the announcement at the Conservative Party conference in Manchester next week.
He will present it as a move designed to boost British business.
Speaking to Sky News on Friday, Hammond said: "This is a clear proposal from the Government to increase the motorway speed limit to 80 miles an hour.
"Principally this is about the huge time savings that would be available by improving journey times, hundreds of millions of pounds worth a year of time savings.
"And also the benefit of bringing millions of ordinary motorists, who are otherwise law abiding, back on the right side of the law because frankly the current speed limit has lost legitimacy."
The increase will be offset with an expansion in the number of 20mph zones in residential areas as part of a compromise agreement with the Liberal Democrats.
Peter Rodger, chief examiner at the Institute of Advanced Motorists, supports a trial of an increase to 80mph on controlled sections of the motorway.
Speaking to The Huffington Post UK, he said: "An increase may yield economic benefits of shorter journey times, but this has to be balanced against the potential road safety issues."
Britain has one of the lowest speed limits in Europe. France has a limit of 80mph while drivers on German autobahns are not subject to a speed limit at all.
However, the proposed raising of the speed limit has alarmed environmental campaigners, who argue that cars use 20 per cent more fuel at higher speeds.
Some road safety campaigners also oppose the move, with charity Brake calling it "shameful".
Brake's chief executive, Mary Williams OBE, said: "The minister Philip Hammond is partially arguing that this move is a good idea because a proportion of drivers break the 70mph limit and that their law breaking needs to be made 'legitimate'. Actions of law breakers should not be legitimised. This is a selfish move that will achieve nothing other than carnage and is pandering to an uninformed few.
"What is far more legitimate is the grief of families bereaved on Britain's motorways in horrendous pile ups at high speed, and the rights of all UK citizens to have slower, not faster, speeds on roads to enable drivers to avoid collisions."
Speaking to The Telegraph, Robert Gifford, of the parliamentary advisory council for transport safety, said: "This will mean a de facto speed limit of 90mph since the police are unlikely to enforce it at speeds below that."
Speaking to The Huffington Post UK, Professor Stephen Glaister, director of the RAC Foundation, said the government must be clear on why they were proposing the changes - for safety, economic or environmental reasons.
"As a society we have to decide what our priorities are and whether gains in one area are worth the trade-offs made in others."
"It's right there should be a review as the existing speed limit has been in place for nearly half a century," he said. "Things have changed: cars are safer, roads are safer.
"There are good reasons for making 80 the new 70, and good reasons not to. Drivers travelling that 10mph quicker might reach their destination sooner, but will use about 20 per cent more fuel and emit 20 per cent 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."
The Guardian reports that energy secretary Chris Huhne was against the increase from 70mph to 80mph as it would create to more pollution.
Huhne's opposition is likely to cause a wry smile among many as he has been dogged by allegations that he illegally got his ex-wife to accept penalty points on his behalf after he was caught speeding.
The current 70mph speed limit for any UK road was set in 1965. The UK's first ever speed restriction was introduced as part of the 1861 Locomotives Act, which set the limit at 10mph.
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