The smaller the stake in any political battle, the more vicious it tends to be.

It may not be clear where this proverb originated – some people attribute it, or a version of it, to former US Secretary of State Henry Kissinger – but both sides in the AV debate seem intent on proving it true.

Their opponents aren’t just wrong, they are “liars”, or possibly “whingers”. Far from being an opportunity to improve Britain’s voting system, supporters of AV portray it as a chance to undermine the coalition and give Nick Clegg or David Cameron, or both, a bloody nose.

Meanwhile, the anti-AV crowd conjure up images of babies denied incubators, or soldiers sent into battle without the right kit, all as a result of AV sucking the Treasury’s coffers dry.

Could all the name-calling and over-the-top rhetoric have something to do with the fact that the change being proposed is a relatively minor one?

Under the Alternative Vote system, each constituency will still return a single MP and leave a large number of voters – the ones who wanted somebody else – disappointed.

Some people may be able to comfort themselves with the knowledge that their second or third or fourth choice got in, but plenty of Tory, Labour or Lib Dem voters don’t support any of their rivals.

Even if they can be persuaded to cast a second preference for the rival party they hate the least, they’ll still have to face the fact that the party they actually supported has lost.

AV also gives you the chance to vote for a smaller party, if you choose.

But only candidates who get a good number of first preference votes will be in with a shout, and that means smaller parties will find it as hard to win as they do now. And if anyone gets more than 50 per cent of first preferences then second preferences won’t even be looked at.