Joe
Please read this link fully: http://www.tuc.org.uk/extras/publicsectorpensions.pdf
It argues the case against the commonly held views about public sector pensions far more succinctly than I ever could!
The whole question of public sector pensions started to be addressed some time ago (as this document shows).
The document also explains very well how, to a great extent, public sector pensions are funded by members' current contributions rather than from another public purse. It suggests that, to change to a system similar to private pension schemes, would require a significantly high input from government to pay for these contributions which would no longer be forthcoming. I'm no accountant so I can't think through the argument very well.