Ringway 3

Ringway 3 was the third from the centre of the series of four London Ringways, ring roads planned in the 1960s to circle London at various distances from the city centre. They were part of a comprehensive scheme developed by the Greater London Council (GLC) to alleviate traffic congestion on the city's road system by providing high speed motorway-standard roads within the capital linking a series of radial roads taking traffic into and out of the city. Most of the scheme was cancelled in 1973.

Ringway 3 was planned as a new motorway running either through or around the periphery of the capital's outer suburbs linking areas such as Barnet, Epping, Dartford, Purley and Chessington. Construction began on the first section of the motorway between South Mimms and Potters Bar in 1973 and the motorway was initially designated as the M16 motorway before its opening.

Whilst the construction of the first section was in progress, the plan for Ringways 3 and 4 was modified considerably. Broadly speaking, the northern and eastern section of Ringway 3 (from the current junction 23 of the M25 motorway with the A1 east and south to the current junction 3 with the M20) was to be built and connected to the southern and western section of Ringway 4 to create the M25. The remaining parts of the two rings became redundant.

The South Mimms to Potters Bar section (junction 23 to junction 24) was opened in 1975, temporarily designated as an A-road (A1178). The remaining sections of the northern Ringway 3 were constructed over the next eleven years: the M25 motorway was completed in 1986 with the opening of the Ringway 4 to Ringway 3 linking section from Micklefield to South Mimms (junction 19 to junction 23).

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