Together with the North Circular Road and Woolwich Ferry, it makes a complete ring-road around Central London and is a former boundary of the Ultra Low Emission Zone.

The remainder of the road was supposed to be of a similar standard but it was repeatedly delayed, and the current route was allocated in the late 1930s to existing urban streets instead.

[1][3] Beyond the common, the South Circular merges with the A3 London to Portsmouth road for two miles, travelling along Wandsworth High Street and passing the old Ram Brewery.

[1][4] The South Circular Road was planned by the Ministry of Transport in the early 20th century as part of a general programme of traffic improvements across London.

[7][8] In 1925, The Times announced a replacement bridge for the Woolwich Ferry was planned as part of the South Circular project to tie in with the East Ham and Barking Bypass (now the A13).

[9] A significant amount of new housing had been built along the route of the South Circular since the original 1903 plans, and building costs had risen because of labour and because of further demolition required.

[13] Sir Patrick Abercrombie was frustrated by the lack of progress, and in 1933 said "There is not a single complete Ring Road in the County or Region of London".

The current recognised route of the South Circular was created by local motoring organisations putting up strategically placed signposts to direct traffic.

Sir Richard Sharples, then MP for Sutton and Cheam, felt this was inadequate and complained that "I do not think that the South Circular Road could be said to exist at all.

However, local Members of Parliament (MPs), including Toby Jessel, MP for Twickenham, complained the project should not be cancelled, as the existing South Circular was completely unacceptable to traffic.

[19] The Government announced a large-scale upgrade of the South Circular in the 1989 white paper Roads for Prosperity, but it was cancelled the following year after a petition signed by 3,500 local residents.

In addition to the proposed property demolition around Tulse Hill, the petition complained that the road's course conveniently avoided a house belonging to then-Prime Minister Margaret Thatcher half a mile away.

Vehicles travelling inside the zone and not meeting key exhaust emission standards will need to pay a daily charge of £12.50 for cars, vans and motorcycles, and £100 for coaches, HGVs and buses.