According to Lynne Featherstone, the Equalities Minister, "civil gay marriages would be law by the next general election despite the strength of opposition from church leaders".
She added, "There is no rolling back whatsoever ... The essential question is not whether we are going to introduce same-sex civil marriage but how." (via John Richardson)
You may be interested to read to Governments Consultative Document here and the Coalition for Marriage website here. Peter Ould is a thoughtful commentator on this issue and he blogs here and is following and writing incisively about the many on-going culture vs gospel debates.