I suppose it would be helpful perhaps to refer you to the referendum that we had in the U.K. in 2011, which was exactly about moving to a different form of voting for the U.K. Westminster Parliament. We called it the AV referendum. We were going to move to an additional vote system if the public had agreed, but the electorate didn't agree, and so we didn't make those changes.
However, the provisions that allowed us to move very quickly toward that referendum when there was a coalition government the election before last were very much based on the 2000 legislation that Andy referred to. So the framework was all there. It was just a question of specific discussion in Parliament about who the franchise should be extended to, when the actual referendum would take place, and what some of the rules would be, but the basic thing was there in the legislation dating back to 2000.
So set up your referendum legislation before you think about the specifics of what your referendum is going to be.