The UK doesn't have the same kind of Freedom of Information Act as the US, or the same conceptual approach towards citizens being owners of the government.
A lot of stuff that is paid for by taxes in the UK is not automatically public domain, but copyright of the government (or technically, Her Majesty's Stationary Office, the govt. printing bureau) and only available on payment of a stiff fee. Basically the state qua legal entity is much more 'selfish' than in the US, where pretty much anything it puts out is public domain by definition, and it's deeply annoying if you're the sort of UK resident with a presumption of that information wants to be free.