Upgrade to England’s largest motorway junction complete

Junction 23 on the M25 in Hertfordshire, the intersection with the A1, is about 1.2km in circumference and sees some of the highest traffic flows on the orbital motorway. 

The works undertaken cost £7.5M and started in August 2019. 

The project has widened the A1 entry slip road, making it a two-lane entry onto the southbound side. This both eases congestion and improves safety. 

The South Mimms services exit at Bignells Corner has been provided with a new lane. The M25 westbound exit slip road has also been widened to accommodate an extra lane. These improvements have made the layout more intuitive for drivers while creating a more free-flowing and safer network in the area around the junction.

A new pedestrian footway between the BP service station and the existing footway has also been created.

Traffic signal timings have also been adjusted to improve the flow around the junction.

National Highways south east regional director Nicola Bell said: “I am delighted that this significant junction upgrade is now fully open. These improvements have already added vital extra capacity and improved journey times for road users.

“The upgraded junction will help to tackle congestion and improve safety for the hundreds of thousands of drivers who use this section of the M25 every day. I would like to thank road users in the area for bearing with us while we got the upgrade complete.”

Connect Plus chief executive Andy Dean said: “We are delighted to support National Highways in the successful delivery of the M25 junction improvement scheme at junction 23. The project’s success is a testament to the skills and collaborative working relationship between National Highways, Connect Plus, Connect Plus Services, Jackson and our supply chain.

“To complete works amidst a global pandemic has presented a number of challenges which our teams have tackled with great determination. We cannot thank them enough for all that’s been accomplished and for the positive impact their efforts will bring to our customers using the strategic road network.”

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