The transport secretary said it was “entirely wrong” that smart motorways were introduced without the right technology to make them safe, but he has ruled out scrapping them.

Grant Shapps told MPs reversing the controversial traffic measure would mean acquiring land the equivalent of 700 Wembley stadium-sized football pitches and destroying large areas of green belt and that instead “we have to make what’s there safe".

Shapps was responding to concerns about smart motorways following an inquest into the deaths of two men on the M1, which found that the roads presented “an ongoing risk of future deaths”.

The South Yorkshire police and crime commissioner has also written an open letter to the transport secretary demanding that they are abandoned.

Shapps told the transport select committee that he inherited the smart motorway concept when he was made secretary of state and he commissioned a report into their safety because he shared people’s concerns.

He said that the results of his stock take showed that fatal casualty rates on smart motorways were lower than on conventional ones.

However, he also said that the rollout of camera technology was too slow.

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He said: “The development of the stop vehicle detection has been greatly improved.

“When I got to the stock take these weren’t going to come in for many, many years and I agree with you that it’s entirely wrong to build a so-called smart motorway without the technology in place to make it safer.

“That’s not the right approach.

“I brought that forward several years at the stock take.

“I have met with Highways England and put pressure on and we are bringing it forward again and we will have stop vehicle detection developed and installed on all of the network.”

Shapps also appeared to dismiss the concerns raised by coroner David Urpeth at the inquest last month, telling MPs he didn’t think “the coroner was aware of the smart motorway stock take and the 18 points and all the measures taken and secondly, may not have been aware of all of the facts with regards to where people die on motorways.

“Sadly, one in 12 fatalities take place on the hard shoulder.

“No fatalities have taken place in emergency areas, because they are set back from the road."