The government is reviewing new ‘smart’ motorways, where the hard shoulder is taken away when busy, after a big increase in near-misses was revealed.

An investigation by BBC Panorama found that on one of two converted sections of the M25, there were 1,485 near misses since the scheme was introduced five years ago.

In the five years before it was a smart motorway, there were only 72 – representing a 20-fold increase.

Smart motorways transform the hard shoulder into another driving lane, leaving motorists who break down in the traffic.

They were intended to reduce congestion on the busiest parts of the road network.

It is understood Transport Secretary Grant Shapps has asked his department to review evidence on the safety of smart motorways, with recommendations expected to follow soon.

The BBC said it believes the government is planning to overhaul the network, fitting radar across the smart motorway system in the next three years.

The car detection system – which is currently only fitted on two sections of the M25 – can spot stranded vehicles as soon as drivers break down. Nationally, motorists currently have to wait an average of 17 minutes to be spotted, and a further 17 minutes before they are rescued.

It also said that dynamic hard shoulders – which sometimes act as hard shoulder but can be opened as traffic lanes – will be scrapped.

Shapps told the BBC: “We absolutely have to have these as safe or safer as regular motorways or we shouldn’t have them at all.”

Sir Mike Penning, the former government minister who approved the roll-out, told Panorama he was misled about the risks of the system.

Sir Mike said: “They are endangering people’s lives. There are people that are being killed and seriously injured on these roads, and it should never have happened.”

Research from the AA found that only 9% of more than 17,000 people questioned feel relaxed or safe driving on a smart motorway.

In addition, just 12% think that smart motorways are as safe as traditional motorways.