M12 Motorway
During the 1960s there were plans for an M12 motorway (also known as the South Woodford - Chelmsford Motorway) which would have run from the North Circular at the base of the current M11 motorway joining the A12 south of Chelmsford or at Brentwood. The North Circular was to be upgraded to motorway-standard as part of Ringway 2 and be designated as the M15 motorway. The M11 was to have provided a motorway standard road into central London past Ringway 1 terminating at the Angel, Islington. The M12 motorway was never built, although the junction of the M11 with the north circular was designed to accommodate it.
Plans for the M12 motorway were withdrawn in March 1994 following a review of the trunk roads program.
Read more about this topic: A12 Road (England)