To many foreign mailers, the UK postcode system is incomprehensible. Since they don't understand it, many of them don't use it, and thus cost themselves £millions in lost revenue and wasted postage. No other country has such a complex postcode system as the United Kingdom.
Within the Royal Mail, there is a section they call the: Blind Letter Duty. Officially, it is called: The Vaguely Addressed Mail Section. Other countries may know it as the Dead Letter Box. The Royal Mail's Blind Letter Duty used to be the best in the world and maintained a 24/7, 264 days-a-year service. With recently introduced competition, and economy cuts to the bone in pursuit of profit, this has changed. It is now a 9am to 4pm five-day-a-week service. Nowadays, the Royal Mail is more inclined to stamp an item: "Return to Sender", than open a page in a reference book. Understand the way the UK postcode system works, and you or your company will benefit. If you don't want to flush money down the toilet, you really have to sit up and pay attention in a way you never had to before.
A UK postcode is a two-part code - an Outward Code and an Inward Code. As an example, let's invent one - TW1 2XA. The TW1 is the Outward Code, and ensures the letter gets to the town of Twickenham. The Inward Code - 2XA is for the convenience of the Royal Mail. The Inward Code helps direct the item to the postperson who is going to deliver to that address. It would be nice to have the complete postcode. But sorters are quite happy to have only the Outward Code. With this information, they can forward the item to an LDO (Local Delivery Office) and let the LDO deal with it using their knowledge - after all, that's what postmen and women are proud of - knowing their local community!
What makes the UK postcode system so unique is that there are three different systems in operation: single letter codes for certain major cities, two letter codes for other towns and cities, and a zone system which applies to London only:
Hopefully, this site will help users both here and abroad to understand our postal system. Together with the Postcode Finder, which registered subscribers can use, your mail should in future get through, whereas in the past it was stamped 'Return to Sender - Insufficient Address' or words to that effect. Here are some (mostly) fictitious examples of what a UK address should look like.
Note: the London postcode zones N1 thru N22 (such as in the example above: (N7 2EQ) are often perceived by foreigners as an abbreviation for 'Number', when in fact it is shorthand for 'North'. Never spell out a postcode as this will only confuse the machines.
An address may often include a county. By tradition English, Scottish, and Welsh counties are known by name only: Kent, Essex, Wiltshire, Lanarkshire, Denbighshire, etc, - the only exception being County Durham because there is a city of the same name - Durham City.
Northern Ireland counties usually have "Co." preceding the name of the county, e.g.: "Co. Fermanagh, Co. Tyrone", etc. Note also that the whole of Northern Ireland has only one postcode prefix - BT for Belfast, but this does not imply the location is anywhere near Belfast. In this respect, BT serves as an area postcode in much the same way as HS for the Hebrides and ZE for the Shetland Isles. Clicking on the link below will give an interesting insight into the evolution of the British Counties during the last thirty years or so, courtesy of Jonathan Rawle:
For UK mailers, a special word of warning. If you think you don't need a postcode because you're posting a letter to a local address, think again! Gone are the days of local filtering. If you live in the Sheffield area, and the local Sheffield Mail Centre is overwhelmed, it will divert its traffic to another Mail Centre, and that may be as far away as London! Mail Centre managers have large screens in front of them and can tell at any time which Mail Centres are at full capacity, and which can handle more work when diverting mail to another Mail Centre. With inter-city hopping planes and good road links, distance is not a problem. We cannot emphasize the fact strongly enough - always use at least the minimum the Outward Postcode. If the item is intended for a local Sheffield address but was sidetracked to another Mail Centre, provided it has an Outward Postcode, there will be little or no delay. But if there is no Outward Postcode, the delay can be days or even weeks. The Royal Mail can even pulp the item!
Below is listed every possible Outward Postcode prefix, the town, city, or area they are derived from, the county where that town, city, or area is located, and the usual abbreviation for the county. The major cities are so well known that it is not necessary to indicate their geographical location, in which case the County column is blank.
|Postcode||Derived From||County or Region||Usual Abbreviation|
|BD||Bradford||West Yorkshire||W Yorks|
|BN||Brighton||East Sussex||E Sussex|
|BT||Belfast||Northern Ireland||N Ireland|
|CV||Coventry||West Midlands||W Midlands|
|DG||Dumfries & Galloway||Scottish Borders|
|DL||Darlington||North Yorkshire||N Yorkshire|
|DN||Doncaster||South Yorkshire||S Yorkshire|
|DY||Dudley||West Midlands||W Midlands|
|EC||East Central London||London|
|GY||Guernsey||Channel Islands (includes Alderney and Sark)||CI (see note)|
|HD||Huddersfield||East Yorkshire||E Yorks|
|HG||Harrogate||North Yorkshire||N Yorks|
|HU||Hull (officially: Kingston-upon-Hull)||East Yorkshire|
|HX||Halifax||West Yorkshire||W Yorks|
|IM||Isle Of Man||Lancashire||IOM (see note)|
|JE||Jersey||Channel Islands||CI (see note)|
|LD||Llandrindod Wells||Mid Wales|
|LS||Leeds||West Yorkshire||W Yorkshire|
|NE||Newcastle Upon Tyne|
|SR||Sunderland||Tyne & Wear|
|WC||West Central London|
|WF||Wakefield||West Yorkshire||W Yorks|
|WS||Walsall||West Midlands||W Midlands|
|WV||Wolverhampton||West Midlands||W Midlands|
|ZE||Zetland (Shetlands)||Shetland Isles|
Note: The Channel Islands (CI), together with the Isle of Man (IOM), have their own postal authorities. The rules regarding undeliverable UK mail without a return address described below do not apply to these authorities because their mail is returned to them for disposal, as they are regarded as independent mail authorities, despite the fact that they are part of the United Kingdom.
Database designers are too inflexible in their approach, designing databases to cater for addresses in their own national format. When a US or UK address is input, it may look acceptable on the screen, but when it comes to printing labels or envelopes, the result is often an unintelligible. The solution is to have a free form address block without any verification, trusting the input operator to type exactly what is in front of him/her.
Many people think that UK PO Box numbers are unique. Not so! Any PO Box number can be assigned to hundreds of firms throughout the UK. It only becomes unique to one particular company when it is used in conjunction with a Postcode. A PO Box number always comes with a postcode, and it is essential that you use it.
Everyone should now have a better understanding of how the UK postcode system works, which was one of the reasons why this website was conceived in the first place by ex-Royal Mail staff. Always use original source documents for addresses whenever possible: business cards, invoices, etc, and make sure your address database is flexible enough to handle addresses in peculiarities of the UK postcode system. Your database manager should be held accountable for this. Remember, your image or the image of your company, is reflected in the way it is able to communicate, and if your correspondence takes weeks instead of days to reach its destination - or even worse, doesn't arrive at all because of a bad or garbled address - it will not reflect favourably on you or your company, and its ability to do international business. It's a global market and if you want to succeed, you have to think globally.