Plans to use more motorway hard shoulders as dedicated driving lanes should be dismissed, according to a Commons committee.

The government has put forward plans to repurpose hundreds of miles of UK motorway hard shoulder into permanent lanes, also known as 'all-lane running', to ease congestion and increase capacity.

Motorway traffic is predicted to increase by as much as 60% from 2010 to 2040, and all-lane running has been seen as a cheaper and less intrusive option than building extra motorway lanes.

However, the Transport Select Committee has released a report claiming the conversion of hard shoulders into full-time driving lanes would be dangerous.

A statement from the committee said: 'We do not support all-lane running as the attendant safety risks have not been fully addressed.

'While the case for increasing motorway capacity is clear, the earlier forms of smart motorway have, by Highways England's own analysis, a lower risk profile than all-lane running.'

Rather than keep the hard shoulder as a permanent driving lane like an 'all-lane running' scheme, 'smart motorways' only open the hard shoulder as a driving lane during peak times or when there are high levels of congestion.

The Department for Transport has said 'all-lane running' had been designed to be as safe for motorists as driving on a normal motorway.

Sections of the M25, M1 and M6 already operate the scheme, and works are under way to extend it to parts of other motorways, including the M3 and M23.

Two trial 'all-lane running' sections on the M25 have seen accidents drop by 17%, and casualty rates fall by 21% during the first year of the test.