The roads minister has heavily criticised speed camera protestors in the Commons.

Answering transport questions in the House on Tuesday, David Jamieson said those who damage speed traps will be responsible for injuries and deaths.

On the day before two men were due to appear in a Staffordshire court charged with vandalising 20 cameras, the minister condemned all similar actions.

"Those people who vandalise cameras are putting people's lives at risk," he said.

"The question they have to answer is if a camera is vandalised and out of action for a period of time, how many more people have been killed and injured?"

Jamieson defended the use of roadside cameras from Conservative criticisms that they have been used to raise money for the Treasury, rather than improve public safety.

He conceded that around five per cent of cameras "are not actually having the effect that we want".

"But does that not mean that 95 per cent are having the effect we want?" he asked MPs.

"We all know what a death is and all the misery that causes but serious injuries include lacerations, crushed or broken limbs, brain injury or sometimes permanent paralysis.

"Any policy to remove the cameras that are successfully driving down those figures must be one the new shadow secretary of state Tim Yeo must want to revoke."

Motorways

Meanwhile transport secretary Alistair Darling is coming under pressure to give the go-ahead to a series of motorway widening projects.

A consortium of motoring and business groups took out full-page adverts in the Independent and Times newspapers on Tuesday calling for cash for the schemes in the upcoming government spending review.

They argued that adding one lane to each of England's five busiest roads would increase capacity by a third.

The move followed a meeting they held with the Cabinet member on Monday.