[npemap-talk] Postcodes & copyright

I have a question. I like the efforts made to collect postcode data by NPE and Free the Postcode, and have contributed data to all three projects. However, I don't understand why collecting postcode data through sites like NPE and Free the Postcode is not infringing Royal Mail's copyright. When I added my postcode to Free the Postcode, the co-ordinates came from my GPS, and I got the postcode from the previous owners, but it must ultimately have come from the Royal Mail.

I don't understand why I did not violate the Royal Mail's copyright, but why getting the postcodes from OSM & search engines (as was previously suggested) would violate copyright.

Can anyone explain the difference?

Russ