The A1023 is an A-road in Essex, England. The road was originally a Roman road which linked London and Colchester. The road is approximately 4.5 miles (7.2 km) long and at its western end is an exit from the Brook Street Roundabout (junction 28 of the M25 and junction 11 of the A12). From there, heading northeast, the road runs through Brentwood as Brook Street, London Road, High Street and Shenfield Road. It then passes by Shenfield as Chelmsford Road before ending at the Mountnessing Roundabout (junction 12 of the A12).