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Route of the A12

The A12 is the main road through deepest Essex, providing access from London to Suffolk and the key ports of Harwich, Felixstowe and Lowestoft. This is one of the few major long-distance routes that was never considered for a blue line — no motorway was ever planned here. Instead, the original Roman Road has been widened where it's in the open and bypassed where it isn't. On a map the A12 looks quite odd, a perfectly straight line with large bumps all along it where it swerves around urban areas.

Between the M25 and Chelmsford, the road was meant to be replaced by a shiny new M12 as recently as the early 1990s. The proposal was simply meant to be a cheaper alternative to widening the existing road. It never got off the ground and the widening was attempted instead — but that seems to have proved problematic. The Brentwood bypass was never widened, and north of there it's three lanes wide to Chelmsford, with the exception of one mile of the Ingatestone bypass, which inexplicably remains just two lanes wide. Recently the three-lane section northbound from Brentwood was reduced to two lanes to alleviate queuing at the point the road narrowed at Ingatestone.

Various other M12 proposals have been floated, but surprisingly none of them were really meant to relieve a substantial part of the A12. The proposals made until the 1980s were only to relieve the section of road within the M25 and not beyond.

You're not looking at the whole A12

This page only deals with the parts of the A12 that are classed as motorway or that have motorway characteristics. Any other sections of this road won't be featured here and will not count towards the mileage shown below.


Start Brentwood (M25)
Finish Ipswich (A14)
Passes Chelmsford, Colchester
Length 53 miles
Connects to M25, A14

With thanks to John Simmons, Matthew Smith, Chris McKenna, Tim Lidbetter and Mick Wilding for information in this section.