BBC News - Gay marriage: Boris Johnson and Michael Gove give backing
This isn't news as such (we've known of Cameron's support for the past couple of years), but new developments in advance of Tuesday's consultation response suggest that, despite some Conservative backbenchers rebelling on the issue, Cameron has the backing of his main rivals, meaning that we're unlikely to see any buckling on the issue.
The fact that Johnson and Gove are both out in support of gay marriage means that there is unlikely to be a single, high-profile opponent of gay marriage proposals which the Government are due to launch on Thursday. Gove, in particular, is significant. There had been speculation of Gove posturing as an heir to Cameron by appealing to Tory traditionalists - it seems that, at least on this issue, Cameron can count on a pretty united Cabinet lacking in any high profile leader of the rebels.
That - combined with support from both Labour and the Lib Dems - means that the UK looks very likely to have introduced gay marriage by 2015.
IMO this will hasten the introduction of gay marriage in Ireland - although the principle in Zappone has been decided (for now) and there is (for now) no compulsion on the part of the Government to recognise foreign marriages, up until now, foreign gay marriages will have been quite rare. Once its legal in the UK, however, then it becomes difficult to see how long a situation can last where someone getting married in Derry won't have that marriage recognised in Donegal.
EDIT: The Consultation Response will be issued today (Tuesday) not Thursday. A Statement to the Commons will be made at 12.30