Recent polls have found that a clear majority of voters support electoral reform, but the latest YouGov survey suggests this is longer the case. The poll puts support for the Alternative Vote (AV) at 39 per cent, just 1 point ahead of first-past-the-post (FPTP) on 38 per cent.
Compare this with a YouGov poll from two weeks ago which put support for AV at 45 per cent compared to 32 per cent for first-past-the-post, and the shift begins to look significant. So what's changed?
The suggestion by Andy Burnham (who dismissed electoral reform as a "fringe pursuit for Guardian-reading classes") and Ed Balls that Labour should consider campaigning against AV can't have helped. It's notable that Labour voters, once strong supporters of reform, now split 42 per cent AV and 40 per cent for FPTP.
The rise in opposition could be interpreted as an expression of resentment against the coalition and, in particular, the Lib Dems. Others in the party have pointed to recent data suggesting that it's now the Tories, not Labour, who would gain most (or lose least) from AV.
Either way, the change is particularly worrying, since the government is still in its honeymoon period. Everyone is aware that the referendum could become a proxy vote on the coalition (or at least the Lib Dems), but few expected support to dip this early.
We'll only start to get a clear idea of the level of support for AV once the campaign proper begins and the arguments are played out in full. As things stand, however, it looks as if the reformists may lose the lead that they'd expected to start with.