Discussing this, a Royal Mail spokesperson said it is "absolutely essential" that you have the correct address and postcode. The expert added: "There can be considerable problems if your details ...

The Royal Mail has shared two letters that can never appear next to each other in a UK postcode. The mail service created the postcode system to maintain a database of deliverable addresses.

Millions of postal addresses are registered on the Royal Mail's Postal Address File with new locations being added to the database all of the time. With new developments in particular ...