name in different localities and the additional locality information is therefore essential if the postcode is wrongly recorded or unknown. Where this is a disambiguating feature, Royal Mail terms this the "dependent locality". For a limited number of addresses a "double dependent locality" line is also required, preceding the dependent locality line: some examples include "Churwell, Morley, Leeds" and "Marton, Sinnington, York". Locality information other than the post town is not always part of the official postal address. In particular, within the London post town, each postcode district name (which can conflict with administrative boundaries, see above) corresponds to a numbered postcode district and is therefore not required in the postal address whenever the postcode is used. For example, "Bethnal Green" is the name of the "E2" postcode district and is optional in the following address: 1 Vallance Road Bethnal Green LONDON E2 1AA If no valid postcode is provided, or if the sorting machine rejects the letter, the use of optional locality or county information may assist manual sorting. In the absence of a full valid postcode, locality often prevents ambiguity where there is more than one street with the same name covered by a post town or postcode district, or where post towns in different counties have the same name. Via Traditionally only, where a place such as a village was served by a post town entirely distinct from its location, the word "Via" or "Near" ("Nr.") was added before the post town. For example: 1 High Street Cuffley Via Potters Bar EN6 1AA However, the Royal Mail discourages this usage because their optical character recognition technology and Mailsort lookup tables check for the post town at the beginning of a line if the postcode is missing, unreadable or incorrect. Additionally, "Near" and "Nr." can be confused with "North". See also Postcode Address File Postcodes in the United Kingdom References Postal addresses in the United Kingdom