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http://blog.okfn.org/2011/10/17/the-cost-of-closed-data-the-economics-of-open-data/
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A total of something like:
£17,850 million.
That, back of the envelope-wise, is what closed data is costing us, the loss through creating artificial scarcity by restricting public sector data to only those pay. Like narrowing an infinitely wide crossing to a small gate just so you can charge – hey, that’s an idea, why not put a toll booth on every bridge in London, that would raise some money – you can do it, but would that really be a good idea?