There are more than 29 MPs severely worried about losing their seats under AV (and they are right to be worried).

The Independent has listed 29 NO2AV MPs who would lose their seats under AV.

As you can see from my previous post, these predictions have severe limitations because they are all based on the flawed assumption that first preferences would remain the same under AV as they did under the current system when we know they would change because of those who admit voting tactically.

We know that first-past-the-post severely distorts the vote, with nationally 20% admitting to voting tactically in general elections. This increases in marginals and when the national result is predicted to be close.

In the close election of 2010 in a very marginal seat maybe up to a third would vote tactically, which could mean the main beneficiaries, Labour in suburban areas in the south and Lib Dems in rural areas in the south and urban areas in the north could see their primary vote plummet under AV by more than half, allowing smaller parties like the Greens and UKIP into play. Especially now the Lib Dems have been discredited.

The lazy prediction that Labour would have won Hove is unlikely to be true, it is more likely it would have been the Greens who benefited. See previous post for details.

About half of safe seats are safe despite the 'winner' getting less than 50% of the vote, but even those seats where the MP does get over 50% can be vulnerable because of the change in voting habits that would happen once people got used to voting how they really want to. This might take a couple of elections to bed down, but it could make the landscape change very quickly. I think the Greens could win 6 or more seats very quickly and UKIP could challenge in a number of previously safe heartland seats for the Tories. It would become very interesting indeed. I think maybe a 100 seats could change hands. No wonder MPs are so worried!