Supplementary vote is neither proportional nor radical

Backing a plan to bring in supplementary vote (having a first and second preference in an election) is hardly radical, as Jack Straw and the government seem to think. Supplementary vote suffers from many of the problems moving away from first-past-the-post should intend to avoid - many ballots will not be counted (in FPTP, any votes not for the top two parties are largely irrelevant; in SV, votes not for the three most popular are largely irrelevant). A huge number of votes are effectively wasted.

What would be radical is a move towards a fully proportional electoral system - one which elects candidates based on their popularity compared to other candidates (the Condorcet winner). A winner under a Condorcet election would clearly have a mandate being the most popular amongst voters - and there would be more of an incentive to vote honestly as all votes count.