About UK Postcodes
Royal Mail introduced postcodes to the United Kingdom between 1959 and 1974. The format of a UK postcode is always one of the following:
The postcode is split into two parts - the part before the space is knows as the outward code and is used to route mail to the correct regional sorting office. The part after the space is known as the inward code and is used to sort the mail into individual delivery rounds from the destination sorting office.
The inward code may only contain letters from the set ABDEFGHJLNPQRSTUWXYZ - not the full alphabet - this is to avoid using letters that when hand-written could be mistaken for other letters or numbers.
For links to useful postcode resources on the Internet, see our links page.