This article is about the original A2212 in Lewisham. For the current A2212 between Lee Green and Bromley, see A2212.
Originally, the A21 ran the whole length of Lewisham High Street. The A2212 ran along Lewis Grove, which was a short A-road parallel to the northern end of the High Street, also connecting with the A20. It is not known exactly why this road was classified as it does not really cut the corner - it may just have been to take traffic away from the High Street.
It is likely that the A2212 became a spur of the A21 early on, as the number was used again when the southern end of the B212 was upgraded to A-road status, possibly in 1935.
With the building of Molesworth Street, the A21 was taken away from Lewisham High Street and the ex-A2212 was declassified. It is now one-way southbound.