Most of the section between Oxford and Solihull is arguably the A44 and the A3400 however its modern course ends northeast to join the M40 from which the northern part of the road can be accessed after one junction of the M42 motorway. A trunk road to Oxford and between Stafford and Stoke on Trent.
In three parts. 1. The London Inner Ring Road at Grosvenor Place to the Victoria one way system. 2. Victoria Street, half of Parliament Square and then Bridge Street (Westminster Bridge). 3. St George's Road (one way (north-west)) past St George's Cathedral, Southwark).
The road has been dubbed "The A three-one-queue" owing to frequent peak-hours' heavy congestion. Part of its course ran from Hatton to Harlington, London across where Heathrow Airport is instead of its present course past Cranford more directly to north-east Hayes and districts further north including Harrow. Its middle section is officially known as The Parkway
Becomes the A4361 between Beckhampton and Swindon. At 195 miles (314 km) is the longest 3 digit A road in the UK. Before the North Devon link road (which was to be B364 before the rerouting) opened, it went northeast via what is now the B3277.
Previously a road between Yarnbrook and Chippenham. Now part of the A350. It was also proposed for the North Devon link road between Barnstaple and Bampton, but it was rerouted and opened as part of the A361 instead.
In the City of Westminster: Sloane Street, Sloane Square, Chelsea Bridge Road, Chelsea Bridge; in the London Borough of Wandsworth: Chelsea Bridge, Queenstown Road (including Queen's Circus); in the London Borough of Lambeth: Queenstown Road, Cedars Road