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. Most recently, in England and Wales a new national address register known as AddressBase has been created by the combination of two of the leading previous address products.

Royal Mail, the national postal service provider, currently 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 has been widely used in the preparation of bulk mailshots and as a sampling frame for surveys.

PAF was for some years combined with Mastermap, the highest resolution digital mapping product from Ordnance Survey, the national mapping agency for Great Britain to form MasterMap Address Layer 2 (AL2), which associated a high resolution Ordnance Survey grid reference to each address. Entirely separately, local authorities maintained 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 assigned UPRNs to each Basic Land and Property Unit (BLPU), which formed the basis for cross-referencing different versions of addresses and against which locations can be recorded.  In the autumn of 2011 the Royal Mail/Ordnance Survey and NLPG address register operations were combined into a new organization, GeoPlace, to produce a new definitive national address register AddressBase, which is distributed by Ordnance Survey.. At present AddressBase freely is available for use by public sector organizations who participate in the Public Sector Mapping Agreement (PSMA) and available for purchase by those outside this agreement. Several versions of the register are provided, varying according to the level of detail provided.

It should be noted that none of these registers is the one used in the operation of the 2011 census, which pre-dated the AddressBase product.. In order to conduct the census by mailing out questionnaires, the Office for National Statistics obtained special licences to use both the MasterMap AL2 and NLPG products and then undertook a large amount of additional work to match and verify these lists, including extensive fieldwork. Information gathered as part of the census operation is treated as confidential, along with individual census responses and hence the improved census address register was used solely for census purposes. It formed the basis for all questionnaire tracking and form matching in the census operation but was effectively a unique single-purpose product, not available for other purposes.