National Address Lists and Standards

A longstanding difficulty when working with UK address data has been that there is no definitive national address list and no universally used standard for addressing.  The same address may be written in several different ways, each of which would be sufficient for everyday use.  However, these will not all contain sufficient information for unambiguous identification, matching or mapping.  A national standard for address referencing, British Standard 7666, provides a template against which the many potential elements of an address (and more) can be recorded and validated, including provision of a unique property reference number (UPRN) but very many address datasets are not BS7666-compliant.

There are important differences between the constituent countries of the UK in how address datasets are recorded and maintained. Significant advances have been made through the construction of a Definitive National Address (DNA) Infrastructure in Scotland and Pointer address information in Northern Ireland, which are national address lists developed jointly between Royal Mail, national mapping agencies and a range of public bodies. In England and Wales by contrast, there are still several separate sources of address information.

Royal Mail, the national postal service provider, maintains a file known as the Postcode Address File (PAF) which contains all addresses to which mail can be delivered and which covers the entire UK.  This file also associates each address with a unit postcode, the most detailed level of the postal code system.  PAF is available for purchase by external users and is widely used in the preparation of bulk mailshots and as a sampling frame for surveys.

This file is used by Ordnance Survey, the national mapping agency for Great Britain, as the basis for its Address-Point product, which associates a high resolution Ordnance Survey grid reference to each address.  A reciprocal system of updates operates whereby Royal Mail and Ordnance Survey share newly found addresses and the two datasets are updated on a continuous basis.  Entirely separately, local authorities maintain address lists for administrative purposes known as Local Land and Property Gazetteers (LLPGs) and these combine to form the National Land and Property Gazetteer (NLPG).  NLPG assigns UPRNs to each Basic Land and Property Unit (BLPU), which forms the basis for cross-referencing different versions of addresses and against which locations can be recorded.  As local authorities are able to access Address-Point through a national Mapping Services Agreement, many NLPG UPRNs are linked to Address-Point locations.  There is, however, no one-to-one match between PAF, Address-Point and the NLPG.  Other organizations such as the fire service and utility companies maintain their own address databases which may or may not be compatible with one of these national lists. NLPG is thus BS7666-compliant.