What is the PAF?

The PAF is the Royal Mail Postal Address File, which contains all of the “known delivery points” in the UK, made up off 1.8 million postcodes and over 30 million residential and business addresses.

When you upload address data to Stannp.com we automatically clean the data and verify the addresses against the PAF File. Addresses that match the data in the PAF file are ‘PAF Matched‘.

A Short History of Postcodes

A postcode is a short address identifier, designed to enable mail carrying services to easily identify and route mail to the correct recipient address. The need for postcodes developed with the growth of city populations and the increasing complexity of the ‘built environment’.

Initially large cities started to be divided into postal districts, for example London was divided into 10 postal districts by 1858, and other large cities followed suit through the 1860s (Liverpool by 1865, Manchester by 1868).

London Postal Districts in 1858

Further growth in population and postal volumes led to the need to divide up and number the districts into ‘sub-districts’.

In London this happened during the First World War as a result of many experience postmen being drafted into the war effort; the Post Office needed to develop a system to allow post to be easily sorted and routed by inexperienced staff who didn’t necessarily know the geography of the district.

The first modern postal code system was introduced in the ‘Ukrainian Soviet Socialist Republicin December 1932, and many countries followed suit over the next few decades. The UK introduced its first postcodes on a trial basis in Norwich in 1959 (because the Norwich sorting office had just been equipped with eight new postal sorting machines), but they were not in nationwide use until 1974.

According to the Universal Postal Union (UPS), around 130 countries use postcodes as part of their addressing systems. Many of these countries also offer online postcode search services; there is a useful directory of these services on the UPS website.

for the UK, the Royal Mail runs the Postcode Finder, which is now one of the top 150 most visited websites in the UK.

How Do UK Postcodes Work?

A UK post code has two components, the ‘Outward Code’ and the ‘Inward Code’. for example, our postcode here at Stannp is EX31 1JZ.

The first group (EX31) is the Outward Code, an alphanumeric code of between 2 and 4 digits, which is used to get the mail piece to the right delivery office. It’s made up of two parts;

  • An Area Code (EX) denoting which part of the country the address is in, and
  • A District Code (31), showing which sub-division of the area that address is in.

All post for that outward code will go to the same delivery office (for EX31, that is the Barnstaple delivery office). Sometimes a delivery office is responsible for several outward codes, (Barnstaple handles EX31, EX32 & EX33).

Image source: Wikipedia

The second group (1JZ) is the Inward Code, which always has 3 alphanumeric characters and is used to route the mail within the district; it tells the delivery office which delivery route the address is on. The inward code is also made up of 2 parts;

  • The ‘sector’ (in our case 1), which is a sub-division of the district, and
  • The ‘unit’ (JZ), which may be a street, part of street, a group of properties, a single property address, or even a department within an organisation.

Postcodes are allocated on the basis of mail volume, a postcode will contain between one and 100 delivery points, with the average postcode containing around 17 delivery points. The number of postcodes changes over time; every month around 3,000 new postcodes are created and 2,500 old ones are removed from use.

What does ‘PAF Matched’ mean?

PAF Matched addresses are those addresses in your data file that 100% agree with the data in the Royal Mail PAF file. The addresses can be machine sorted by Royal Mail, and will receive the maximum postal discount available (which we pass on to you, our customers).

Addresses that don’t PAF match can still be sent and in most cases will be successfully delivered, but they incur an additional cost as they have to be hand sorted by Royal Mail staff rather than being automatically sorted by machine.

How is a non-PAF Matched address still deliverable?

A non-PAF matched address simply means that the data you have for the address is not 100% the same as the data for that address in the Royal Mail PAF file.

For example, unregistered house names can often cause an address to fail PAF matching. The address in your data file might be ‘The Maltings, 96 High Street, Barnstaple, EX31 1HX.’

If the owner of the property hasn’t registered their house name with Royal Mail, the PAF file will not have ‘The Maltings‘ as part of that address, the address will fail PAF match and have to be hand sorted.

However, as long as the house number and postcode are correct, the mail piece will be delivered to the correct delivery office, that office will sort it onto the correct delivery route, and the postman or postwoman responsible for that round will deliver it to you intended recipient.

Why Didn’t My Data PAF Match?

An non-PAF matched address means the data you have for the address record is not 100% the same as the data for that same address in the Royal Mail PAF file.

Common reasons for PAF match failures include;

  • Misspellings; part of the address has be miss-typed when the data was gathered.
  • False Address; The address given to you by your intended recipient was is not a real address, (either deliberately falsified or miss remembered)
  • Postcode Error; As described above, a correct postcode is the most important part of the mail delivery system. Even if the rest of the address is correct, an error in the postcode will cause the address to fail PAF matching.
  • New Address; The property is recently constructed and hasn’t yet been added to the PAF file. (Note, this can still be the case even if the property has a valid postcode).
  • Alias Error; As in the example above, the property owner has given the property a name but hasn’t registered that name with Royal Mail so it’s not part of the PAF file. This error can also occur if the address does have a registered alias, but that alias is not included in your address data.
  • Business Name Error; Unlike residential addresses, business names form part of their registered addresses and are included in the PAF file. This can cause otherwise correct addresses to fail PAF match where the business name has been abbreviated, or the business is using a trading name etc.

Bonus Topic: Interesting Postcode Facts!

UK Postcodes Overseas; There are 15 UK postcodes that are not (geographically) in the UK, used for sending post to British overseas territories. These include;

Space Postcodes (fictional); The ship In the comedy Red Dwarf has a postal address complete with postcode: Red Dwarf, Deep Space, RE1 3DW.

Space Postcodes (real); The International Space Station has it’s own postal address, thanks to the Low Earth Orbit (LEO) addressing system developed by Don Pettit, Flight Engineer for ISS Expedition 31 in 2012.

Don worked out that his address on ISS would be; Node 2, Deck 5, ISS, LEO 51.603. The postcode is derived from the orbital inclination of the station (51.6 degrees), and the last two digits are designation for the particular space station, with ISS being the third in this location (after Salyut and Mir).

Postcode Saturation; Tesco is the only retailer to have achieved ‘postcode saturation’, they have had at least one store in every postcode area of the UK.

That’s a BIG garden; In 2008 then footballer (now football manager) Steven Gerrard built a two storey gym in his back garden of his Merseyside home. It was so big it had a different postcode to his house.

Famous Postcodes; Some postcodes have become almost as famous as the places and people they belong to;

  • SW1A 1AA – Buckingham Palace
  • SW1A 0AA – Palace of Westminster (Parliament)
  • SW19 – Wimbledon
  • SAN TA1 – Father Christmas’ very own postcode.

Life Imitating Art; in 1985 The BBC TV series Eastenders started using the fictional postcode area “E20” for addresses in Albert Square. in 2011 E20 became a real postcode area when the Olympic Park district was created for the 2012 London Olympic Games.

Room to Grow; Despite Royal Mail adding around 3,000 new postcodes a month there is no danger of the system running out of postcodes anytime soon, the seven digit alpha-numeric system has enough combinations to create at least 48 million postcodes (with around 1.8 million post codes currently in use).

We hope you find our PAF Matching, Postcodes and Data Cleaning Guide useful and interesting. For more helpful hints, tips, guides and info you can find us on TwitterFacebook and LinkedIn, or feel free to speak to your account manager if you have any questions or need any help.

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