The Highways Agency is looking to increase the amount of ‘managed motorway’ on the network – sections where the overall speed of traffic is adjusted up and down to avoid traffic jams and to allow the use of hard-shoulder running.

Currently sections of the M25 and M40 operate variable speed limits

Under new plans however cameras will be placed on large sections of motorway designed to catch drivers exceeding the overall 70mph limit.

Mooted plans suggest that over 100 miles of the busiest motorways will have the new-style cameras, with over 400 miles of the network eventually covered.

Julie Townsend, deputy chief executive of Brake, the road safety charity, said: "Speed cameras are an extremely well evidenced, cost-effective way to improve safety and reduce deaths and injuries on roads where they are placed, preventing families going through the trauma of a sudden bereavement or life-changing injury.

"Put simply: speed cameras reduce speeding, which helps to prevent deadly crashes. Breaking the speed limit is risky and illegal, so only drivers who break the law will face fines."