text: These were introduced because mail was often sent to the wrong place, e.g., to St Helena instead of St Helens, Merseyside or St Helens, Isle of Wight. and to Edinburgh instead of Edinburgh, Tristan da Cunha, and many online companies would not accept addresses without a postcode. Mail from the UK continues to be treated as international, not inland, and sufficient postage must be used.
  Bermuda has developed its own postcode system, with unique postcodes for street and PO Box addresses, as have the Cayman Islands, Montserrat and the British Virgin Islands. Montserrat recently introduced postal codes, and a system has been under consideration in Gibraltar with the code GX11 1AA being introduced as the generic postcode for the territory in the interim.
  The separate postal code systems for those territories are shown below:
  The British Sovereign Base Areas of Akrotiri and Dhekelia in Cyprus use Cypriot postal codes for civilian use. The British military use BFPO addresses.
  British Forces Post Office (BFPO)
  The British Forces Post Office (BFPO) provides a postal service to HM Forces separate from that provided by Royal Mail in the United Kingdom, with BFPO addresses used for the delivery of mail in the UK and around the world. BFPO codes such as "BFPO 801" serve the same function as postal codes for civilian addresses, with the last line of the address consisting of "BFPO" followed a space and a number of 1 to 4 digits.