The area is roughly the combined area of the London Boroughs of Tower Hamlets, Newham and Waltham Forest. Also, the eastern part of the London Borough of Hackney, the western sections of the London Boroughs of Redbridge and Barking and Dagenham and a small part of the Epping Forest District and Essex are within the postcode area.

The area includes the London Borough of Southwark and Lewisham, the Royal Borough of Greenwich, the eastern part of the London Borough of Lambeth, the northern part of the London Borough of Croydon, the western part of the London Borough of Bexley and the northwestern part of the London Borough of Bromley.

This area covers most of the London Borough of Havering (including Romford, Hornchurch, Rainham and Upminster), the eastern part of the London Borough of Barking and Dagenham (including Dagenham itself) and a small part of the London Borough of Redbridge. In Essex, the area covers most of the Thurrock district (including Grays, Purfleet, South Ockenden and Tilbury), also small parts of the Epping Forest District of the Borough of Brentwood

The area includes much of the London Borough of Redbridge, the western part of the London Borough of Barking and Dagenham, and the southwestern part of the Epping Forest district of Essex. The western part covers a small part of the London Borough of Waltham Forest and London Borough of Newham