Railway bridge over St Marys Lane (B187) in Cranham, Essex
The B187 is a short urban B-road into Upminster from the east.
It starts on the B186 at Puddle Dock, on the edge of Cranham. It heads west, going under the M25 almost immediately. It soon enters the urban area at Cranham. It goes under a railway line at Wantz Bridge before ending at a set of traffic lights, which is known as Bell Corner, in the centre of Upminster. All four arms have different numbers: to the right is unclassified; to the left is the B1421; straight on is the A124.
The A124 here was numbered B187 until after World War II, therefore the B187 continued west through Hornchurch to end on the A125 on the south side of Romford.