Specifically Code-Point Open: https://www.ordnancesurvey.co.uk/products/code-point-open which is updated quarterly, and in turn gets the postcodes from Royal Mail.
Something is missing here. If OS already has that data from RM and can make it available freely, why would they need to build another database?
Specifically Code-Point Open: https://www.ordnancesurvey.co.uk/products/code-point-open which is updated quarterly, and in turn gets the postcodes from Royal Mail.