I've noted before that the biggest problem for the pro-AV campaign is that even its own supporters aren't keen on the system. Ben Bradshaw, for instance, who is now leading a Labour campaign for AV, told the New Statesman last year:

The reason I've never supported AV is that it would have given us an even bigger majority in 1997, and it would have given the Tories an even bigger majority in 1983, and probably 1987 as well.

Now, Alan Johnson, usually one of Labour's strongest supporters of electoral reform, has admitted that he's struggling to get excited about next May's referendum. In an interview with Fabian Review, he said:

I'll support AV, but my heart won't be in it in the same way as if it was the proper thing.

It's difficult to find anyone who's passionate about the system that Nick Clegg memorably described as a "miserable little compromise". At best, the Alternative Vote attracts lukewarm support from those who long for a genuinely proportional voting method. The Electoral Reform Society, for instance, which is bankrolling the Yes campaign, issued a press release just hours before the coalition was formed, pointing out that "AV would prove a very modest reform . . . Significant regional imbalances would remain between main parties."

The referendum won't be won or lost at Westminster, but it must be dispiriting for the Yes camp that so few politicians are prepared to lend it their wholehearted support.

A letter signed by 20 new Labour and Conservative MPs including Nick Boles, Tristram Hunt and Zac Goldsmith today rejects AV on the grounds that it is not a "priority" for the public. It's a hackneyed argument, but it's true that public support for reform has plummeted in recent months.

If the Yes camp is to stand a chance of winning the referendum, it will need to overcome public apathy. With this in mind, it might want to begin with its own supporters.