It sounds rather like a middle-class sex position, doesn’t it? But if you ignore that (and get that image out of your head – that took me a while…) and read this Political Betting post:

So here we are – what many MPs are hoping will be the low point for them in the whole expenses saga – the publication today of the Legg Report…

The general theory, backed up by election after election, is that incumbent MPs get an electoral bonus. Could this affair see that produce the opposite. Will 2010 be marked by the “reverse incumbency effect”?

What this is implying is that the MPs expenses saga could mean that all sitting MPs – regardless of party or the extent to which they are personally caught up in it – will see their electorate turn against them simply because they are an existing MP. I can see a lot of play in this in constituencies where MPs have been made to repay money by Legg (especially substantial amounts of money), but not really very much when the local MP has been cleared.

I can only really see the reverse incumbency effect making a significant difference in areas where the individual MP has been pulled up by Legg over their expenses. However, candidates may well be able to make a small amount of traction out of it anyway through making general points about MP expensres and declaring they will openly declare everything that they have claimed.

But I don’t think that people are angry beyond reason or have significantly more trust in wannabe-MPs than in existing MPs. Some MPs who have been in the news may see their vote diminish through expenses, but I don’t think this has even neutralised the usual incumbency effect in most cases, let alone turned it on its head.