A421 Marsh Leys Roundabout to Black Cat Roundabout road markings - 24 November 2025 to February 2026

We’ll work overnight (8pm-6am) on weeknights only.

We'll work from Monday 24 November 2025 to Saturday 28 February 2026, weather permitting.

Closures

We'll continue our work in January 2026.

Tuesday 6 January to Tuesday 20 January 2026 - A421 eastbound Renhold junction to Black Cat Roundabout

Diversion:

• exit at Cardington roundabout onto the A603 (Cambridge Road)
• continue onto Bedford Road and then Sandy Road
• join the A1 northbound to Black Cat Roundabout 

A421 eastbound Renhold junction to Black Cat Roundabout diversion map.

Wednesday 7 January to Friday 9 January 2026 - A421 eastbound A600 exit slip road

Diversion:

• continue on A421 eastbound
• exit at Cardington roundabout onto Cardington Road
• continue onto Cambridge Road and Harrowden Road 

A421 eastbound A600 exit slip road diversion map.

Tuesday 20 January to Wednesday 31 January 2026 – A421 westbound Black Cat Roundabout to Renhold junction

Diversion:

• take the A1 southbound to Sandy Roundabout
• continue on A603 Sandy Road, Bedford Road & Cambridge Road
• rejoin the A421 at Cardington roundabout

A421 westbound Black Cat Roundabout to Renhold junction diversion map.

We'll update this page with February 2026 closures when we have firm details.

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.