The A421 will be closed in both directions between Renhold and Black Cat roundabout for two weekends in November.

The roads will be shut while National Highways install six large steel beams for the new Roxton Road bridge, marking a milestone on the £1 billion A428 Black Cat to Caxton Gibbet Improvements.

The work will be carried out from 9pm on Friday November 1 to 5am on Monday November 4 and then from 9pm on Friday November 8 to 5am on Monday November 11.

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 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.  

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.

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.