The Church of England will not perform gay marriage blessings. It also will not ordain clergy who are in gay marriages.
The Pastoral Guide detailing this position affirms that Our Lord taught that marriage is an indissoluble union between one man and one woman. It allows homosexuals and their families, including those who are not living a life of chastity, to participate in the sacraments.
From The Church of England’s House of Bishops Pastoral Guidance on Same Sex Marriage:
… As bishops we have reflected and prayed together about these developments. As our statement of 27th January indicated, we are not all in agreement about every aspect of the Church’s response. However we are all in agreement that the Christian understanding and doctrine of marriage as a lifelong union between one man and one woman remains unchanged.
… ‘The Church of England affirms, according to our Lord’s teaching, that marriage is in its nature a union permanent and lifelong, for better for worse, till death them do part, of one man with one woman.”
… The victimisation or diminishment of human beings whose affections happen to be ordered towards people of the same sex is anathema to us. We assure homosexual people that they are children of God, loved and valued by him, and deserving of the best we can give of pastoral care and friendship.