Conservative voters aren’t really resolutely against AV either. Polling shows that a good 10-20% are open to voting Yes in May, no doubt because they live in areas where they would actually see a benefit to such a change while currently not getting the wins that they probably do deserve.

Wasn’t Boris Johnson elected on some kind of AV system?

“trying to speculate how a previous election would have turned out if the electoral system was different is futile. It doesn’t take into account tactical voting at that time given FPTP’s own bias.”

More importantly, all of this retro-fitting results to systems business is based on an era when over 40% of Lib Dem voters had Labour as their second preference. That’s now under 20%.

Quite apart from the arguments of principle, AV would be electorally damaging for Labour for the foreseeable future.

“More importantly, all of this retro-fitting results to systems business is based on an era when over 40% of Lib Dem voters had Labour as their second preference. That’s now under 20%.”

This is also a terrible and misleading set of statistics to use. Around half of the Lib Dem support has vanished and turned up under Labour’s support statistics. It’s no good saying that Labour would now lose out, because the reality is more likely to be that seats that were marginal Lib Dem/Labour will now become Labour easy wins, and those seats where Labour were second behind the Tories will see Labour gaining first preference votes rather than the second that they would have go in 2010.

All in all, this kind of statistical manipulation ignores that local issues are what drives people to certain parties. If Labour are the largest party in their constituency, and the Lib Dems are third, then it’s more likely that the Lib Dems are more inclined to be Labour supporters in that area due to the local politics showing a preference towards Left type policies. Vice versa for the corresponding Tory situation.

Also, focusing on whether system X or Y benefits your own party is a stupidly tribal way of looking at things. You should make the argument that it is better for the country.

@5, what’s best for the country is what benefits my party.

“those seats where Labour were second behind the Tories will see Labour gaining first preference votes rather than the second that they would have go in 2010.”

Sure, so Labour is more likely to win them under a future First Past The Post election, but less likely to do so under AV, where those extra first preferences from former Lib Dems can be overwhelmed by the Tory second preferences of Coalition Liberals, and in many cased by bulk transfers from UKIP.