Work is due to start on adding lay-bys to smart motorways after a long-running campaign to make them safer.

In December last year, it was announced the M20 and M25 were among the routes where “emergency areas” were to be installed at the side of the carriageway.

Painted bright orange, the 100m pull-in areas will be equipped with telephones linking directly to traffic control rooms.

Nine will be added to the M25 between Junction 5 near Sevenoaks and Junction 7 at the M23 turn-off.

Four will go on the M20 between Junction 3 at Swanley and Junction 5 at Aylesford.

Work is expected to start at the end of this month.

It comes after drivers and campaigners raised concerns about having no hard shoulder to use in an emergency.

“Safety is our highest priority and we have listened to drivers' concerns about having more places to stop in an emergency on motorways which don’t have a permanent hard shoulder…”

In 2021, Chatham and Aylesford MP Tracey Crouch called on the government to carry out an urgent review into smart motorways to avoid "future tragedies" after two men were killed when a lorry ploughed into their vehicles while they were stationary on the M1 in South Yorkshire.

National Highways project sponsor Felicity Clayton says the scheme will “boost public confidence” in smart motorways.

She added: “Safety is our highest priority and we have listened to drivers' concerns about having more places to stop in an emergency on motorways which don’t have a permanent hard shoulder.”

For the upgrades to be carried out the left-hand lane will be closed throughout construction.

The other lanes will stay open with a 50mph speed limit.

All existing emergency areas will remain open wherever possible throughout construction and a free recovery service will be available in the roadworks.

The project is part of a nationwide safety programme with more than 150 areas being built, 52 of which are in the South East.

It is being funded by the government.