The B149 is a short B-road in south Essex. Originally unclassified it soon became the A1089. However, road improvements in the area in the 1970s downgraded the road and gave it its current number.
The road starts at a roundabout on the A1013 in Little Thurrock and heads southeast along Wood View, a residential road that was obviously D2 once but one lane in each direction has now been taken away for parking and cycle access. It's not long before a grade-separated junction (GSJ) is met and the B149 TOTSOs.
The road ahead, now D2, continues south to provide somewhat circuitous access to the A1089; this was the main through route before that road's present alignment was built. The GSJ is theoretically a half-diamond but the southbound offslip is for buses only. B149 traffic follows a two-way road to cut off the corner before reaching traffic lights where it TOTSOs left; westbound traffic follows the straight road here and does use the GSJ onslip.
Wood View continues east and soon goes over the A1089. There's a brief glimpse of fields either side of the bridge after which a roundabout is reached which provides access to Chadwell St Mary. We continue ahead on the village's bypass and descend, with views over to Tilbury Power Station, to another roundabout where we meet another road into the village. The B149 ends here on the A126.