First off I thought this was an April Fool's joke - Make data collected at the tax payer's expense available to said tax payers - impossible I thought.

but the BBC article looked genuine.

Mind - all of the "open data" links seem to be broken so perhaps I was right the first time....

OS Maps seem to have been made freely available for a while as part of some sites, e.g. the wonderful Geograph site:

http://www.geograph.org.uk/