Harvard professor Niall Ferguson has once again apologised for making homophobic remarks about economist John Maynard Keynes, claiming that his friendship with the prominent gay blogger Andrew Sullivan shows that he could not be homophobic.

Ferguson had already apologised on his website for claiming that Keynes – who died in 1946 – did not care about the future because he was bisexual and had no children.

Writing for the Spectator, Ferguson said: “This was doubly stupid. First, it is obvious that people who do not have children also care about future generations. Second, I had forgotten that Keynes’s wife Lydia miscarried.”

He continued: “I was duly attacked for my remarks and offered an immediate and unqualified apology. But this did not suffice for some critics, who insisted that I was guilty not just of stupidity but also of homophobia. I have no doubt that at least some students were influenced by these allegations. Nobody would want to study with a bigot. I therefore owe it to students — former and prospective — to make it unambiguously clear that I am no such thing.”

Ferguson then cited his friendship with gay US-based blogger Andrew Sullivan and said: “The charge of homophobia is equally easy to refute. If I really were a ‘gay-basher’, as some headline writers so crassly suggested, why would I have asked Andrew Sullivan, of all people, to be the godfather of one of my sons, or to give one of the readings at my wedding?”

Meanwhile, columnist Douglas Murray has defended Ferguson in a Spectator article, writing: “As it happens I don’t think Niall Ferguson needed to apologise for making this comment. The attempt to shut down debate to such an extent that a glib off-the-cuff comment such as this can be subjected to such souped-up outrage is another reminder that the left-wing search for what it thinks of as ‘equality’ has become little more than an attempt to ignore any and all differences that exist in the world.”