The Postcode Address File (PAF) is a database which contains all known "Delivery Points" and postcodes in the United Kingdom. Buildings which contain several flats or businesses but only one external front door, will only have the external front door listed; the full addresses which include flat numbers, floors etc., are excluded from the PAF.

This address is used as a routing instruction by Royal Mail staff to sort and deliver mail quickly and accurately. However, it is not always a geographically accurate description of where a property is located. For example, in Outer London

Outer London

Outer London is the name for the group of London Boroughs that form a ring around Inner London.These were areas that were not part of the County of London and became formally part of Greater London in 1965...

, where the former home county name is often (and incorrectly) used in the penultimate line of an address.

The PAF is a collection of over 28 million Royal Mail postal addresses and UK postcodes. It includes Small User Residential, Small User Organisation and Large User Organisation details. It is available in a variety of formats including Digital Audio Tape

Digital Audio Tape

Digital Audio Tape is a signal recording and playback medium developed by Sony and introduced in 1987. In appearance it is similar to a compact audio cassette, using 4 mm magnetic tape enclosed in a protective shell, but is roughly half the size at 73 mm × 54 mm × 10.5 mm. As...

 and compact disc. A charge is made for lookup services or wholesale supply of PAF data.

Structure of the file

Element	Field name	Max length
Organisation	Organisation Name	60
	Department Name	60
Premises	Sub Building Name	30
	Building Name	50
	Building Number	4
Thoroughfare	Dependent Thoroughfare Name	60
	Dependent Thoroughfare Descriptor	20
	Thoroughfare Name	60
	Thoroughfare Descriptor	20
Locality	Double Dependent Locality	35
	Dependent Locality	35
	Post Town Post town A post town is a required part of all postal addresses in the United Kingdom, and a basic unit of the postal delivery system. Including the correct post town in the address increases the chances of a letter or parcel being delivered on time. Post towns are usually based upon the location of...	30
Postcode	Postcode	7
PO Box	PO Box	6

Alias data

The Alias File is a supplementary file containing additional data which are not part of official postal addresses, including details that have changed over time, or have been amended by the public and then used. This file is used to identify these elements and cross-reference with the official postal address.

The Alias File holds four types of record: Locality, Thoroughfare, Delivery Point Alias, and County Alias:

• The Locality record - holds short forms, local names, and 'postally-not-required' (PNRL) details.
• The Thoroughfare record - contains replacement street and road names for a given locality, thoroughfare or dependent thoroughfare combination.
• The Delivery Point Alias record - holds additional information at given addresses, such as trading names and building names.
• The County record - holds traditional
  Counties of the United Kingdom
  The counties of the United Kingdom are subnational divisions of the United Kingdom, used for the purposes of administrative, geographical and political demarcation. By the Middle Ages counties had become established as a unit of local government, at least in England. By the early 17th century all...
  
  , administrative
  Administrative county
  An administrative county was an administrative division in England and Wales and Ireland used for the purposes of local government. They are now abolished, although in Northern Ireland their former areas are used as the basis for lieutenancy....
  
   and postal county
  Postal counties of the United Kingdom
  The postal counties of the United Kingdom, now known officially as the former postal counties, were postal subdivisions in routine use by the Royal Mail until 1996. The raison d'être of the postal county – as opposed to any other kind of county – was to aid the sorting of mail by...
  
   information.

Royal Mail, in their guide to the data products imply that the county alias information was provided when Royal Mail removed the former postal county from the main file.

Errors

Royal Mail acknowledges that the PAF contains errors, and publishes forms for submitting error reports. A very small number of addresses are not listed correctly, and others (especially new developments) may not be listed at all for a period of time.

Costs and public availability

Between 2004 and 2006 a consultation was taken about the future management of the PAF. The proposal to release it for use at low or no cost was rejected, and the business model where it was used to raise money from profitable corporations was retained.

The balance sheet for the PAF for 2005/6 disclosed an income of £18million, 8.6% of which was profit.

Following a Government consultation, on 1 April 2010 Ordnance Survey released co-ordinate data for all Great Britain

Great Britain

Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...

 postcodes (but not their address elements) for re-use free of charge under an attribution-only license, as part of OS OpenData.

External links

• PAF from Royal Mail
• [ftp://ftp.royalmail.com/Downloads/public/cmwalk/doc/active/doc21800003/DIGEST%207%20MASTER%203sep09.pdf Technical guide to using the PAF file] - A document that explains the PAF file in some detail.
• Alias File from Royal Mail
• GB postcode geolocation file (excludes Northern Ireland)