[1] The commission was set up in December 1997 by the Labour government with the support of the Liberal Democrats, to investigate alternatives to the single member plurality (or "first past the post") electoral system used for British general elections.
The commission was asked to take into account four requirements: The commission reported in September 1998 and suggested the alternative vote top-up or AV+ system, which would directly elect some MPs by the alternative vote, with a number of additional members elected from top up lists similarly to Mixed-member proportional representation.
The commission considered a single transferable vote system but rejected it because it would require massive constituencies of around 350,000 electors resulting in an oppressive degree of choice (i.e. too many candidates to choose from).
Finally, Jenkins rejected STV because it was a different system from those used in European and devolved parliaments, as well as the London Assembly.
However, the eventual coalition's deal – between the Liberal Democrats and the Conservatives – specified that there would be a referendum on "the introduction of the Alternative Vote".