The B414 is an urban B-road in west London.
Originally it started on the A5 Kilburn High Road just to the south of the station and headed southwest along Cambridge Avenue before zigzagging into Kilburn Park Road. Now, however, the route has been moved slightly so that it follows Kilburn Park Road from the A5. Cambridge Avenue, meanwhile can no longer be followed in its entirety.
After going past St Augustine's church the B414 reaches a set of traffic lights where the B413 comes in from the west. The road ahead is a multiplex with the B414 dominant and this situation continues until the far end of Kilburn Park Road is met. Here is a T-junction where the B413 turns left and B414 turns right.
After a short distance heading west the B414 TOTSOs left at a set of traffic lights onto Walterton Road, which is one-way. It continues southwest before reaching the Maida Hill Piazza. Traffic from Walterton Road must turn sharply right here onto Fernhead Road. However, the B414 crosses the Piazza (apparently on foot) onto Elgin Avenue and then ends at a set of traffic lights with the A404 and A4207. It is interesting that the road is still classified when it is impossible to follow it in full, although some maps (like the one on the right) show the road as following Chippenham Road to reach Elgin Avenue - a route that is accessible in the car.