A421 in Bedfordshire to close for two weekends as National Highways lifts bridge beams into place

National Highways will close the A421 in Bedfordshire over the first two weekends of November to install six massive steel beams for the new Roxton Road bridge, marking a major milestone on the £1 billion A428 Black Cat to Caxton Gibbet Improvements.

This flagship scheme will transform journeys between Milton Keynes, Bedford, and Cambridge, improving connectivity and reducing travel times across the region.

To complete the complex operation, the A421 will be closed in both directions between Renhold and Black Cat roundabout, as well as the existing Roxton Road bridge, during the following periods:

• 9pm Friday 1 November to 5am Monday 4 November 2024
• 9pm Friday 8 November to 5am Monday 11 November 2024

During the closures, specialist crews will use a 750-tonne crane to manoeuvre six massive steel beams into place over the A421. These beams will form the backbone of the new Roxton Road bridge, providing the strength and stability to safely support traffic for years to come.

Each beam is a staggering 130 tonnes in weight and 37 metres in length – approximately the same weight as a fully grown blue whale and length of a Boeing 737 aircraft.

Once the beams are securely in place, work will begin on the structure – known as formwork – that will support the surface of the new bridge.  

Gareth Moores, National Highways Programme Manager, said: “The scale and complexity of this engineering feat cannot be overstated and marks a significant moment for our scheme. Each beam will be carefully lifted into place – inch-by-inch – using a 750-tonne crane, forming the backbone of the new Roxton Road bridge.

“We understand road closures can be inconvenient, but it’s important to remember that the majority of work so far has been completed while keeping the A421 open to traffic. Closing the road ensures we can complete this beam lift safely, protecting both our workers and the travelling public.”

The new Roxton Road bridge is essential to accommodate the new westbound slip road and eastbound free-flow link from the A421 onto the A1. The dimensions of the current bridge cannot support these much-needed upgrades.

The £1 billion A428 scheme is National Highways largest infrastructure scheme currently under construction. It will transform journeys for thousands of drivers, cutting average travel times by up to 10 minutes - a saving of up to 1.5 hours over the course of a working week.

The scheme will deliver a new 10-mile dual carriageway linking the A1 and A421 Black Cat roundabout in Bedfordshire with the A428 Caxton Gibbet roundabout in Cambridgeshire. Both roundabouts will be upgraded to modern, free-flowing junctions, vastly improving traffic flow and reducing congestion.

The scheme is expected to open to traffic in 2027.     

Diversions

Closure of A421 between Renhold and Black Cat roundabout (both directions)

• Travelling via A421 eastbound - eastbound traffic diverted via the A603 at Cardington to A1 northbound at Sandy to Black Cat roundabout  
• Travelling via A421 westbound - westbound traffic via the A1 Black Cat roundabout southbound to Sandy to the A603 to join the A421 westbound at Cardington. 

Closure of Roxton Road bridge

• Travelling north on Roxton Road - traffic will be diverted north up Roxton Road until they reach the junction with The Lane. Road users will then head east on The Lane until they reach the junction with the A1 northbound. Road users will travel north to Wyboston and then down the A1 southbound towards the Black Cat roundabout.  
• Travelling south on Roxton Road - traffic will be diverted north up the A1 until they reach the junction with The Lane. Road users will then travel west on The Lane where they will then travel south down Roxton Road.  

Notes to Editors

National Highways is the wholly government-owned company responsible for modernising, maintaining and operating England’s motorways and major A roads.

Real-time traffic information for England’s motorways and major A roads is available via the Traffic England website, local and national radio travel bulletins, electronic road signs and mobile apps. Local Twitter services are also available.

For further information please contact National Highways' press office (24hrs) on 0844 693 1448 and select the most appropriate option:

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