The inspirational Free Our Data blog out of the UK reports on a mention of their efforts in Parliament, where Mark Todd, MP had this to say in argument against:

I should like briefly to comment on the free our data campaign [our emphasis], which has suggested that the correct path is to distribute Government data virtually for free, or at cost. The difficulty of that model, which relies on the argument that that would generate substantial economic growth and tax revenues that would easily repay the amount lost in revenues directly associated with the sales, is that I am afraid it places a substantial reliance on any Government—not just this one—to continue to fund the development and maintenance of the quality of data in those organisations. At the moment, the organisations have revenue streams on which they can rely to invest into the future. Simply relying on the Treasury to bury its hand into its pocket periodically to develop data into the future is wishful thinking. That is not the path down which we should be treading.

More of the debate can be found here.