Definition of A124

The road begins at a junction with the A13 road at Canning Town station in the south west of the London Borough of Newham. The road continues in a north easterly direction for 3 miles (4.9 km) as Barking Road, passing through West Ham, Plaistow and East Ham.

The road passes into the London Borough of Barking and Dagenham at a crossing of the River Roding and there forms a junction with the North Circular Road. The road bypasses Barking town centre as the Northern Relief Road and is then called Longbridge Road for 2 miles (3.2 km), forming a short section of dual carriageway and part of the borough boundary with the London Borough of Redbridge.