There's an excellent article in today's Technology supplement of the Guardian newspaper on the need for free public access to data for which the taxpayer has already paid.
The authors make the case on the basis of economics, pointing out the the present policy of selling data militates against the development of businesses that could develop services, as well as putting an additional load on public agencies, some of which have collected the data in the first place!
No one can be surprised that the fault lies with the Thatcher regime and its "Making a business of information" strategy of the 1980s, when the idea of the 'information society' first hit and the Treasury realised it might make a little money - unfortunately, it is not making much, whereas in the USA, which makes information of this kind freely available, the impact upon the economy has been significant.
The authors point to an interesting paper by Peter Weiss - I recommend clicking on the link - it takes you to a badly designed Web page, but you'll find a link to a Word document, which is much more readable.