I'll elaborate. Towards the end of the last parliament, there was an orgy of dimwitted hatred directed towards politicians. Not least on here. The LibDems, the most political of parties, were playing this anti-politics game for all they were worth, just like they wittered on about expenses until David Laws got caught. Labour felt compelled to offer something on voting reform, but didn't want STV. The author of the Labour manifesto threw AV in, despite never being on record as supporting it before, in the knowledge that it would probably get nowhere. I forget the author's name. He's MP for somewhere in Yorkshire.
Alex - good of you to recite from your Big Book of LibDem Quotes About A Voting System We Hated Until Ten Minutes Ago.