Chancellor backs controversial bill

The proposals have sparked determined resistance from campaigners for traditional marriage, and many Tory backbenchers are expected to oppose them when the legislation comes before Parliament, where they have been promised a free vote.

But Mr Osborne, who is in charge of Conservative preparations for the 2015 general election, yesterday warned that polls indicate a “clear majority” in favour of the change, particularly among the young and women.

In an analysis of Barack Obama’s victory in last week’s US presidential election, Mr Osborne said that Mitt Romney’s prospects were undermined by the sense that the Republicans were out of step with modern America on social issues.

The Chancellor told The Times: “I should declare my personal position on these social issues: I wouldn’t change the current abortion laws and I strongly support gay marriage on principle.”