The B223 is an urban B-road in south London, running parallel to the Chatham Main Line.
It starts on the A23 between the two railway bridges by Brixton station. It heads southeast along Atlantic Road, going under a railway line and crossing the A2217 at a set of traffic lights.
The B223 continues south along Railton Road as far as Herne Hill station, the next on the line. There is a one-way system here. Southbound traffic follows the original line of the B223 to the end of Railton Road to meet the A215 at a complicated set of traffic lights at the corner of Brockwell Park. Northbound traffic leaves the A2214 slightly further west before heading north along Hurst Street.