I just signed up to a petition about postcodes.
The context is that Royal Mail asked someone to stop giving not-for-profit websites access to postcode data. From a database copyright perspective, Royal Mail is within its rights to do this; but it seems wrong that socially useful non-commercial sites are unable to make use of postcodes without paying a high license fee.
Compare this to the US, where this data is freely available.
However, why stop with non-commercial sites? The economic boost to small businesses from a freely-available postcode database would likely exceed the revenue made via licensing.
Meanwhile, of course, OpenStreetMap will continue to improve its postcode coverage until the whole question becomes moot.