The A1(M) will be closed between Welwyn and Stevenage for two weeks from Monday as a £4.5 million project to tackle ‘pinch-points’ gets underway.

The congestion easing roadworks will take place between Junction 4 for Hatfield and Junction 7 for Stevenage.

Phase one will take place along the 9.5mile stretch between 10pm and 6am from Monday, December 8 to Friday, December 23.

It will involve improving the existing northbound carriageway and slip roads at Junction 6, new overhead gantries, new surfacing on the road, new road markings, new safety fencing and improved drainage.

The new layout will see lane one leave the motorway at Junction 6 and lanes two and three continue on to Junction 7.

It is hoped this will remove the bottleneck within the junction where lanes two and three currently merge.

Nightime closures will be back in place when phase two work begins on Monday, January 5 and end on Friday, January 16.

The second phase will involve closing the hard shoulder and lane one in both northbound and southbound directions between junctions 5 and 6.

A 50mph speed limit will be installed.

Full closures of the A1(M) will be required towards the end of the scheme in order to erect the new overhead gantries and further information will be provided in advance of these closures.

Subject to weather conditions, the work is scheduled to last for approximately four months until the end of March.

During the overnight closures a clearly signed diversion route will be in place.

For northbound traffic at junction 4 motorists will be diverted along the A6129, A1000, B197 and A602 to re-join the A1(M) at junction 7.

Highways agency project manager Mark Saunders said: “This is great news for drivers travelling on the A1(M) in Hertfordshire as it will improve traffic flow between junctions 6 and 7.

“By changing the layout of the A1(M) in this busy location the flow of traffic through the junction will be improved.

“We’ll also be improving the on-slip by extending the slip road to give a greater distance for traffic to merge with existing A1(M) traffic.

“It will have a positive impact on drivers using this important junction. Once complete, the scheme will cut congestion and reduce journey times, and improve safety for drivers using this junction.”