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 20 October 2025 - Potton Road and the B1046, St Neots Road weekend closure

We're installing new drainage systems along Potton Road and the B1046, St Neots Road.

Closure

We will close Potton Road, and the B1046, St Neots Road for the weekend from 8pm Friday 17 to 6am Monday 20 October 2025.

Diversions

For B1046, St Neots Road:
  • head south on Barford Road, then take the first exit onto the A428 eastbound
  • head south on the B1040 at Eltisley
  • continue south before heading west on the B1046, Gransden Road to rejoin St Neots Road. 
For Potton Road:
  • head south on Barford Road, then take the first exit onto the A428 eastbound
  • head south on the B1040 at Eltisley
  • continue south through Waresley and then west along Gamlingay Road
  • leave the B1040 onto Drove Road and then head north onto Tetworth Hill
  • head west on Drewels Lane and continue onto Potton Road.

Potton Road and the B1046, St Neots diversion map.

Works

We're installing new safety barriers and street lighting along the A421 westbound carriageway. 

Closure and diversion 

We'll close the A421 westbound between Black Cat roundabout and Renhold interchange, and the A1 northbound between Tempsford and Wyboston, and Bedford Road overnight on the following dates:

  • Monday 13 to Friday 17 October 2025 (9pm to 5am)
  • Monday 20 to Friday 25 October 2025 (9pm to 5am)

We'll divert traffic:

  • continue south on the A1 towards Sandy and then travel west on the A603 towards Bedford
  • rejoin the A421 at Cardington interchange

See A421 and A1 overnight closures diversion route map

We are installing new drainage systems and gullies on the A428 between Eltisley and Caxton Gibbet roundabout

Closure

We'll close the A428 between Eltisley and Caxton Gibbet roundabout from 6am Saturday 25 to 6am Monday 27 October 2025.

Diversion

  • head north on the B1040
  • take the second exit onto the A1198 eastbound
  • take the A1198 to rejoin the A428

A428 Eltisley and Caxton Gibbett roundabout diversion map.

We're installing beams for the new bridge at Kelpie Marine.

Closure

We'll close the A1 northbound between Tempsford and Black Cat roundabout for the weekend from 9pm Friday 31 October to 5am Monday 3 November 2025

Diversion

  • leave the A1 at Tempsford
  • head north on Tempsford and St Neots Road
  • then head west on the A428 to rejoin the A1

A1 northbound diversion map.

We are installing a culvert close to the A1 carriageway.

Closure

We'll close the A1 in both directions between Tempsford and Black Cat roundabout for the weekend from 9pm Friday 7 to 5am Monday 10 November 2025.

Diversion

If your heading northbound:

  • leave the A1 at Tempsford
  • head north on Tempsford and St Neots Road
  • then head west on the A428 to rejoin the A1 

If you're heading southbound, follow this diversion in the opposite direction.

A1 north and southbound diversion map.

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 - 18 August 2025

From Monday 18 August, we will open three new sections of road at Black Cat roundabout, linking in with the existing road network. These are:

  • A421 eastbound to A1 northbound free-flow link
  • A421 westbound on-slip
  • Realigned Bedford Road

A421 eastbound traffic will no longer approach the Black Cat roundabout, instead taking the single-lane free-flow link directly onto the A1 northbound.

The northern section of Black Cat roundabout will remain closed restricting movement from the A421 onto the A1 southbound.

The A1 northbound and A1 southbound approaches to the Black Cat roundabout will remain unchanged.

Black Cat roundabout layout map from August 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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