The B142 is a short B-road in east London. The road was unclassified in 1922 but gained its current number before 1950.
The road starts at traffic lights on the A11 Bow Road just east of Bow Church DLR station. It heads north along Fairfield Road passing Bow Garage (a Stagecoach depot) before going under the DLR and the Great Eastern Main Line. Soon a mini-roundabout is met. A spur of the B142 heads right along Tredegar Road to reach a diamond interchange on the A12.
The B142 mainline bears left then TOTSOs right onto Parnell Road. It continues north, meeting the B119 Roman Road (known for its market) before ending a short distance further on at traffic lights. Left is the B118 whilst the other two directions are unclassified. The B118 used to head right as well before construction of what is now the A12 severed the road.