Musket.
The previous government put forward a bill on equality. A bill they had a manifesto mandate for. On that basis, the coalition government felt it right to honour the bill as the calling of the election was the only thing preventing its passing into law. So we have equality legislation. Full stop and in line with prevailing human rights legislation.

As Labour's Bill made no mention of same-sex marriage, what is YOUR point Musket?
This idea came from nowhere to become a flagship policy which Cameron is "determined" to put into force within this Parliament.
No manifesto mentions.
To mention in the Queen's Speech about Government intentions.
It is indeed Cameron's whim, and has come out of the blue.
Tory Blue.