M25 Junction 23 improvements complete 

Junction 23 on the M25 in Hertfordshire is the largest junction on England’s motorway network, connecting the M25 with the A1 (M) for Hatfield and South Mimms. At about 1.2km in circumference, the junction sees some of the highest traffic flows on the M25. 

A £7.5m upgrade to the junction began in August 2019, including widening of the Southbound A1 entry slip road to provide a two-lane entry onto the Southbound A1. 

The upgrade also sees a new footway for pedestrians from the BP service station to the existing footway. 

As well as improving safety, the transformation has made the junction safer and easier for drivers and includes an upgrade of the traffic signal timings to improve flow through the junction. 

A new lane at the Bignells Corner exit from South Mimms services, with a widening of the M25 westbound exit slip road to accommodate an additional lane has made the layout more intuitive as drivers approach the junction. 

This has created a more free-flowing and safer network in the area around the junction, helping to accommodate local traffic and improving safety for users, including those using the junction to travel to and from the M25 and wider destinations in the UK. 

Connect Plus and strategic chain partner Connect Plus Services are responsible for operating and maintaining the M25 network, on behalf of National Highways. This includes all adjoining trunk and slip roads. 

Andy Dean, Connect Plus chief executive, 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.”