UK’s £1bn road project reaches halfway point

The nation’s biggest road-building scheme — costing £1m per day at its peak — has now crossed the halfway mark.

National Highways is constructing a new 10-mile dual carriageway from the notorious Black Cat roundabout near Roxton in Bedfordshire to the Caxton Gibbet roundabout near Cambourne in Cambridgeshire.

According to National Highways, it will cut journey times between Milton Keynes and Cambridge and improve links to the ports of Felixstowe and Harwich. It will also ease congestion at the Black Cat roundabout, which handles nearly 80,000 vehicles daily.

Overall, the project, which began in December 2023, will cost about £1bn and is scheduled to open in spring 2027.

Paul Salmon, senior project manager at National Highways, said the team reached the halfway stage on schedule and within budget, calling it a "major milestone".

"The single-carriageway A428 has caused significant issues for the area over many years," he said.

"The Black Cat is infamous for delays, crashes, and safety concerns, and this scheme addresses all of that. It will get traffic moving."

The project, which employs around 850 people across site and office roles, was at its busiest over the summer during the earthworks phase.

What improvements are being made?

• Black Cat roundabout

Creating a modern three-level junction linking the A1, A421, and nearby local roads.

A1 traffic will pass below ground level in a new purpose-built cutting. A421 traffic will cross above on a new flyover. Local roads, including Bedford Road, will remain at ground level, making it simple to switch between routes.

• Viaduct across the River Great Ouse

Building a 240-metre viaduct over the River Great Ouse to span the river near the Black Cat roundabout between Roxton and Little Barford.

• Bridge over the railway

A new bridge will carry thousands of drivers safely over the East Coast Main Line railway. This is one of the UK’s busiest rail routes, running north–south between London and Edinburgh.

• St Neots junction

A new junction at Cambridge Road, just east of St Neots. Two ground-level roundabouts are linked by a bridge over the dual carriageway, which runs in a cutting below.

The new junction will offer better access to the town centre and train station. Drivers can now join or leave the new dual carriageway here, making journeys quicker, simpler, and safer.

• Caxton Gibbet roundabout

Upgrading the Caxton Gibbet roundabout in Cambridgeshire into a modern, two-level junction. It will connect the new A421 dual carriageway with the A428 and A1198.

Traffic on the new dual carriageway will pass over the junction on a newly built flyover bridge. Local traffic between the A428 and A1198 will continue to use the ground-level roads.