Buffeted by frequent criticism from all sides, and particularly pressured by those who like to style themselves exclusive upholders of traditional biblical faith and morality, Dr Williams told an audience in Edinburgh that he "regularly questioned" himself on this matter.
He was talking at the International Book Festival, in conversation with well-known rabbi Baroness Julia Neuberger, who has championed the rights and dignity of LGBT people.
On the issue of his failure to support them, “I know that is what a great many of my gay and lesbian friends would say that I did,” the former archbishop declared.
“I look back and I think, ‘at what point would it have been constructive to do something different that would have made a difference and take us forward?’, and I don’t know, it’s quite soon to say," he added.
“It’s a slow fuse. The best thing I can say is that that is a question which I ask myself really rather a lot, and I don’t quite know the answer.”
Dr Williams, a noted intellectual and theologian, retired as senior cleric in the Established Church, and head of the overwhelmingly non-Established 78 million-strong worldwide Anglican Communion in December 2012.
He has taken up an academic post in Cambridge.