The road was originally designed to connect local industrial communities together in addition to bypassing London, and was constructed in the 1920s and 1930s. It received significant upgrades after World War II, and was at one point planned to be upgraded to motorway as part of the controversial and ultimately cancelled London Ringways scheme in the late 1960s. In the early 1990s, the road was extended to bypass Barking and meet the A13 north of Woolwich; the section south from here to the ferry, in Beckton and North Woolwich, are labelled the A1020 and A117 respectively, instead of A406.