The Archbishop of Canterbury has been talking - in the context of the gay marriage debate - whether the government has a "mandate" for this proposed regulation:
“The basis of the mandate for changing the state’s understanding of marriage given the lack of any commitment in the election manifestos of the main parties has been one of the many issues raised in those discussions.”
Which rather begs an important question. Or rather indicates Dr Williams to be displaying a degree of constitutional ignorance that doesn't become his standing. True, it is commonplace for people engaging in debate to suggest that a government doesn't have a "mandate" for something. But this is just blather - there's an acceptance that proposals based on manifesto promises aren't nobbled by the House of Lords but nowhere in all this does it say that the government is limited in its actions by the contents of a manifesto published before an election.
The government has every right to propose changes to the law regardless of whether the matter being considered (gay marriage in this case) was or wasn't within a political party's election manifesto. And I'm pretty sure that Dr Williams knows this to be so, which makes his statement merely political roustabout rather than a serious constitutional point.