Diversions, closures and speed restrictions

Check this page regularly for the latest updates on road closures, diversions, and speed restrictions

Diversions, closures and speed restrictions

Current closures

17 to 21 November 2025 - A1 northbound and A421 eastbound overnight closures

Anglian Water is installing a new connection to the water main near the A1 carriageway. 

Closure

We'll close the A1 northbound between Black Cat roundabout and Wyboston, and the A421 eastbound between Renhold and Black Cat roundabout from Monday 17 to Friday 21 November 2025 (9pm to 5am).

Diversions

A1 northbound diversion:

  • exit the A1 at Tempsford onto St Neots Road towards St Neots
  • take A428 exit re-joining the A1 at Wyboston

A421 eastbound diversion:

  • exit A421 at Cardington Interchange onto the A603 towards Sandy
  • at Sandy, join the A1 northbound
  • exit the A1 at Tempsford onto St Neots Road towards St Neots
  • take A428 exit re-joining the A1 at Wyboston

See A1 northbound and A421 eastbound diversion route map

We're changing the road layout at Black Cat roundabout.

Closures

From 9pm Friday 21 to 5am Monday 24 November 2025, we'll close:

  • A1 northbound between Tempsford and Black Cat roundabout
  • A421 westbound between Renhold and Black Cat roundabout
  • Bedford Road in both directions between Roxton Garden Centre and Black Cat roundabout

A421 westbound diversion

  • travel south on the A1
  • take the A603 towards Bedford
  • re-join the A421 at Cardington interchange

A1 northbound diversion

  • leave the A1 northbound at Tempsford
  • head north on Barford Road towards St Neots
  • re-join the A1 northbound at Wyboston.

A1 west and northbound diversion map.

We're moving existing and installing new utility services under the A1198 carriageway.  

Closure 

We'll close the A1198 between the Caxton Gibbet southern roundabout and the entrance to the Caxton Gibbet services in both directions.

The closure will run from 8pm Friday 28 November to 6am Monday 1 December 2025. 

A1198 diversion

If you're travelling southbound:

  • take the A428 east towards Cambourne
  • then take the M11 south
  • Rejoin the A1198 via A603

If you're travelling northbound, follow the same diversion in the opposite direction.

Please remember that closures can change at short notice. You can check the latest information on our daily closures page or find live travel information on our Traffic England site. Our travel alerts give details of live incidents on our network.

Long term changes

Black Cat roundabout layout change - 24 November 2025

From Monday 24 November, we'll open new sections of road at Black Cat roundabout, linking with existing road networks. 

A1 southbound

We’re moving the A1 southbound onto a new stretch of road passing under the new east bridge at Black Cat roundabout.

Make sure you’re in the correct lane before you reach the junction:
  • left hand lane for A1 south, A421 or M1
  • right hand lane for A1 north, A421 or M1

A1 northbound

We’re moving the A1 northbound approach onto the new northbound on-slip at Black Cat roundabout.

Make sure you’re in the correct lane before you reach the junction:
  • left hand lane for A421 west and Bedford Road
  • right hand lane for A1 north

Map of Black Cat roundabout layout from November 2025.

Let us know what you think

Use our A428 Black Cat to Caxton Gibbet improvements feedback tool to have your say.

This tool features an interactive map, allowing you to click on specific locations to leave targeted comments or provide general feedback.

ECHO is a one-way feedback tool, so if you'd like a response to your feedback you can email the project team at info@a428.co.uk.

Planning diversions, traffic management and speed limits 

What you can expect to see

The A1, A421, and A428 will mostly stay open while we carry out our work.

There may be some overnight and full weekend closures from time to time. We'll need these for important tasks like:

  • connecting new and existing roads
  • building bridges
  • delivering large pieces of equipment or materials.

We're committed to being a good neighbour. That’s why we’re carefully planning our work to reduce any disruption to drivers and the local community.

Highest safe speed through roadworks

We’ve determined that a temporary speed limit of 40mph is needed to keep both road users and our workers safe.

This reduced speed limit helps junctions function as usual, which means we won’t need to close roads as often

How we choose diversion routes

We're dedicated to ensuring that any traffic diversions around road closures are safe and appropriate. We'll use diversion routes that can handle the type and amount of traffic being redirected.

The diversion routes will mainly follow major A roads to avoid heavy traffic on local streets. We'll work with local authorities to agree on the best routes.

These diversions are required by law, based on the development consent order (similar to our official approval or planning permission).

To minimise disruption, we will manage traffic carefully, providing clear signs and advance warnings to drivers.

 

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