Home > Important roadworks information: A12 between junctions 29 (Crown Interchange) and 33 (Copdock Interchange) – improvement work

Important roadworks information: A12 between junctions 29 (Crown Interchange) and 33 (Copdock Interchange) – improvement work

30 October 2025

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A communication from National Highways -

Important roadworks information

A12 between junctions 29 (Crown Interchange) and 33 (Copdock Interchange) – improvement work 

We are continuing our works on the A12. This work will include resurfacing, refreshing road markings, replacing worn-out studs. Once complete, drivers will enjoy a safer, smoother, and better-defined road surface. 

This work is part of a bigger project on the A12 between Crown Interchange and Copdock. We’ll share details of any future closures and diversions as soon as they’re confirmed. 

We plan to complete this work over one week from Monday 3 November 2025. We will work between 9pm and 5am weeknights only, weather permitting.  

Closures and diversions 

To carry out the work safely, we will need to close sections of the A12, and divert traffic as detailed in the table below: 

 

Closure 

Dates 

Diversion 

A12 southbound junction 33 (Copdock) to junction 32b and junction 32A to Birchwood junction

Monday 3 November to Friday 7 November

Diversion route for southbound A12 via junction 33 (Copdock Roundabout): 

  • Continue on the A14 to junction 56. 
  • Join the A137 southbound towards Ardleigh. 
  • Follow the road into Colchester. 
  • At the roundabout, take the second exit onto St Andrews Avenue. 
  • Take the second exit again onto Cowdray Avenue. 
  • Go through The Albert Roundabout and continue onto Colne Bank Avenue. 
  • At Colne Bank Roundabout, take the second exit onto Cymberline Way (A133). 
  • At Spring Lane Roundabout, take the second exit onto the fast link slip road to rejoin the A12 southbound at junction 27. 
  • You can then continue your journey south on the A12. 

 

Map of the diversion can be found below . 

How to find out more 

To find out more about the scheme, please visit our dedicated website page at: https://nationalhighways.co.uk/our-roads/east/ 

To find out more about road improvements we’re carrying out across the East of England, please visit our website at https://nationalhighways.co.uk/our-work/east/.   

If you would like more information, please contact us on 0300 123 5000, or by email at  info@nationalhighways.co.uk.  

Diversion Route2