New Public Popular Edition maps are trying to create a freely usable UK postcode database. The
British Post Office owns the database of postcodes and their corresponding coordinates (in Europe, there are more expansive copyrights over factual material like postcodes than in the US, where collections of non-original facts receive a very thin protection). That means that your website can only use post-codes if you buy a license from the Post Office.
New Public Popular Edition (along with a similar project, Free the Postcode) is trying to solve this. They have 1950s-era public-domain maps and they ask you to locate your house (or childhood home) on it and key in your post-code. They do the rest, eventually building out a complete database of every postcode in Britain.
The resulting data will be released as purely public domain — no restrictions whatsoever on re-use.
Link
(via Plasticbag)