Baroness Warsi gave a speech yesterday arguing AV would benefit extreme parties:

“AV gives more power to those people – fringe voters, Monster Raving Loonies, and yes, fascists – who are voting for precisely the kind of extreme policies most people want to marginalise.

“You don’t need me to tell you that this represents a serious danger to our democracy. It means that bigots will be given more power in our politics and extremists will look to gain more influence over mainstream parties.

“The danger is that under AV, our whole political system would take a giant leap backwards, becoming more warped and disproportionate as fringe voters hold sway.”