Downing Street always knew tomorrow’s gay marriage vote was going to provoke tensions. But what’s interesting is how unsure Number 10 is about how to approach the free vote on the issue.

The whips are not supposed to get involved on these votes, and besides a number of those normally twisting colleagues’ arms to extract some loyalty are considering voting against the bill. But there are around 50 Tories whose votes will mean the difference between a Conservative majority for the legislation. Even though David Cameron is, as James explained in his column yesterday, personally committed to the legislation as a matter of principle, finding himself in the minority of his own party will dent his modernising zeal. As Peter Kellner points out this morning, only 17 per cent of voters say the Tories have best ‘succeeded in moving on and left its past behind’, so there is much still to do.

What can the Prime Minister do to tempt those wavering MPs into the ‘aye’ lobby tomorrow? Well, The Times reported this morning that he would speak out in favour of the legislation ahead of the vote. But this morning, Cameron’s official spokesman poured cold water on this, saying:

‘I’m certainly not aware of any plans at all for the Prime Minister to do that. As you know, it is a free vote.’

The danger, even in informal meetings between the PM and his MPs, and a last-minute statement, is that the party looks panicked and as though it is trying to corral unwilling MPs through the lobbies on a free vote.

Tags: Conservatives, David Cameron, Gay Marriage, UK politics