Disruption - A 23-mile diversion route will be in place (Image: Google Maps/ National Highways)During this stage, the northbound carriageway will remain shut overnight until October 10. Drivers will be diverted along a lengthy 23-mile route via the A131 and A120, passing through areas including Braintree and Little Waltham. For northbound journeys, motorists will be directed off the A12 at junction 19 onto the A131, before re-joining at junction 25 via the A120. Southbound drivers will follow the same route in reverse. Road users are being advised to plan ahead, allow extra time for journeys and follow clearly signed diversion routes during the overnight closures.