Maidstone is the county town of Kent. It is roughly in the middle of the traditional Country of Kent and is the headquarters of modern Kent Council.
A bypass of Maidstone had been planned since the 1930s, but was only completed in 1961, as the first section of what's now the M20 (then called A20(M)).
Maidstone in 1926
Route B2 proposals late 60s
By the 1950s congestion in the town resulted in proposals for an inner ring road. The first known plan dates from 1961 which shows a dual carriageway with roundabouts. This forms a tighter loop around the north of the town centre than subsequent proposals by running to the south of the prison. Along with the inner ring road there would also have been another route further out to cater for through traffic. The earliest proposal is for a Route A running to the south of the inner ring road. This would have been elevated and start at the A20 at each end.
Over the next few years other routes were evaluated. They were given letters from B to D. A, C and D were eventually discarded leaving only the B routes were later broken down to B1, B2 and B3. The B routes all run north-south to the west of the town centre. They all start at the Wheatsheaf in the south and head north to either the A20 (B and B1) or A229 (B2). The clear favourite was B2 which would remove the most traffic from the town centre. Property had started being acquired in the vicinity of the large Westborough Interchange.
Route B3 proposals 1970
Concerns were raised about the amount of property required and the disturbance to the area around Westborough Interchange, not least from residents who realised their homes would be affected once the plans were published. A route running nearer the railway was therefore investigated and found to be superior on amenity grounds involving far less demolition. This route was known as B3 and became the agreed line of the road in 1970 and the former protected line of B2 was abandoned with the acquired property resold. The scheme by now was known as the Western Relief Road.
The inner ring road meanwhile also went through various revisions until the layout was finalised in around 1967. The northern section would now pass to the north of the prison. It was anticipated the B3 road wouldn't be built for some time so the inner ring road would have to handle all through traffic in the meantime hence the GSJ at Upper/Lower Stone Street. Construction would be in three phases. The western side would be built first, then the south and finally the northeast. The western side was built much as planned including the large roundabout over the river. The rest was never completed although part of the southeast section was built later although not to the original proposals.
These proposals lingered on for a few years during the early 1970s but were abandoned sometime around 1974 when local government reorganisation and the effects of the oil crisis killed similar schemes up and down the country. The proposals didn't completely die however. Watered down plans saw the A229 between the town centre and Sandling Interchange dualled in the early 90s which feeds directly into the western side of the inner ring road, something the original plans didn't feature.