As soon as the government announced plans to bring in gay marriage, it was clear that the press was going to turn the vote on it into a referendum among Tory MPs on Cameroon modernisation. Even, though, it is a ‘free vote’, a failure to secure the support of at least half the parliamentary party for the bill was going to be treated as a blow to Cameron’s authority. But rather than leaning into this fight, Cameron has shied away from it. Absurdly, he isn’t even on the front bench for the opening of today’s debate and one has to go back months for his last major public statement on the issue.

Cameron’s decision to vacate the field is a mistake for several reasons. First, no one explains the Conservative case for gay marriage better than him. His absence has denied Conservative campaigners on this issue their best weapon. If he had led, more Conservatives would have followed and voted yes tonight.

Second, if Cameron had made clear how important he views this issue as more Conservative MPs would have supported it. Certainly, I suspect it would have changed the calculation for a fair few of those MPs who are voting no to keep their constituency associations happy.

Finally, this reticence is all too typical of how the Cameroons back away from a scrap. This failure means that there’s now a peer pressure to rebel in the Conservative parliamentary party. It is, in a dramatic change from the 1980s, loyalist MPs who shrink from going into the tea room or to meetings of the 1922.

Number 10 have made other mistakes on this issue. They should have reassured Tory MPs about their motives by making clear that a marriage tax allowance would be introduced as soon as gay marriage was through; demonstrating that this is about strengthening the institution of marriage rather than just political symbolism.

The result of all this is that those counting the votes for Number 10 now expect that they’ll fail to secure the support of a majority of parliamentary party and that there’s a considerable chance that more Conservative MPs will vote against it than for it.

Tags: David Cameron, Gay Marriage, UK politics