A series of overnight closures is planned on the northbound A12 this week, affecting junctions between Chelmsford, Witham, Kelvedon and Colchester for maintenance and horticultural work on behalf of National Highways.
All the closures below run overnight, with National Highways advising drivers to check before they travel and allow extra time for their journeys.
Monday, June 8
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A12 northbound J16 entry slip road closed
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Time: 9pm to 11pm on Monday, June 8, 2026
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Reason: Horticulture works (cutting and planting) – A12 both directions Copdock Roundabout to J11
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A12 northbound J17 entry slip road closed
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Time: 11pm on Monday, June 8 to 1am on Tuesday, June 9, 2026
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Reason: Horticulture works – A12 both directions Copdock Roundabout to J11
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A12 northbound J15 to J19 main carriageway closed
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Time: 9pm on Monday, June 8 to 5am on Tuesday, June 9, 2026
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Reason: White lining and road markings – A12 both directions J11 to J19
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A12 northbound J21 main carriageway closed
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Time: 9pm on Monday, June 8 to 5am on Tuesday, June 9, 2026
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Reason: Structural reconstruction at J21
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Tuesday, June 9
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A12 northbound J18 entry slip road closed
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Time: 1am to 3am on Tuesday, June 9, 2026
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Reason: Horticulture works – A12 both directions Copdock Roundabout to J11
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A12 northbound J18 exit slip road closed
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Time: 3am to 5am on Tuesday, June 9, 2026
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Reason: Horticulture works – A12 both directions Copdock Roundabout to J11
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A12 northbound J19 entry slip road closed
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Time: 9pm on Tuesday, June 9 to 12.01am on Wednesday, June 10, 2026
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Reason: Horticulture works – A12 both directions Copdock Roundabout to J11
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A12 northbound J20A exit slip closed
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Time: 12.01am to 3am on Wednesday, June 10, 2026
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Reason: Horticulture works – A12 both directions Copdock Roundabout to J11
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A12 northbound J21 entry slip closed
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Time: 3am to 5am on Wednesday, June 10, 2026
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Reason: Horticulture works – A12 both directions Copdock Roundabout to J11
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A12 northbound J15 to J19 main carriageway closed
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Time: 9pm on Tuesday, June 9 to 5am on Wednesday, June 10, 2026
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Reason: White lining and road markings – A12 both directions J11 to J19
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Wednesday, June 10
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A12 northbound J22 entry slip closed
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Time: 9pm to 11pm on Wednesday, June 10, 2026
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Reason: Horticulture works – A12 both directions Copdock Roundabout to J11
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A12 northbound J22 exit slip closed
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Time: 11pm on Wednesday, June 10 to 2am on Thursday, June 11, 2026
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Reason: Horticulture works – A12 both directions Copdock Roundabout to J11
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A12 northbound J23 exit slip closed
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Time: 2am to 5am on Thursday, June 11, 2026
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Reason: Horticulture works – A12 both directions Copdock Roundabout to J11
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A12 northbound J15 to J19 main carriageway closed
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Time: 9pm on Wednesday, June 10 to 5am on Thursday, June 11, 2026
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Reason: White lining and road markings – A12 both directions J11 to J19
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Thursday, June 11
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A12 northbound J24 entry slip closed
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Time: 9pm to 11pm on Thursday, June 11, 2026
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Reason: Horticulture works – A12 both directions Copdock Roundabout to J11
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A12 northbound J25 exit slip closed
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Time: 11pm on Thursday, June 11 to 2am on Friday, June 12, 2026
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Reason: Horticulture works – A12 both directions Copdock Roundabout to J11
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A12 northbound J26 entry slip closed
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Time: 2am to 5am on Friday, June 12, 2026
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Reason: Horticulture works – A12 both directions Copdock Roundabout to J11
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A12 northbound J15 to J19 main carriageway closed
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Time: 9pm on Thursday, June 11 to 5am on Friday, June 12, 2026
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Reason: White lining and road markings – A12 both directions J11 to J19
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National Highways says closures are weather-dependent and may change at short notice, with signed diversion routes in place during works.
