A Harvard professor, broadcaster and Financial Times columnist who apologised last week for making homophobic comments about a famed bisexual economist, is facing claims that he has a history of making similar comments.

Niall Ferguson, speaking at the Tenth Annual Altegris Conference in Carlsbad, said that John Maynard Keynes was an “effete” member of society and that he took a selfish world view, and did not care about future generations, because of his sexuality and lack of children.

The British-born historian later apologised, but critics have now questioned his claims that his comments at the conference were “off-the-cuff”, and pointed to a 1998 book, in which he makes similar comments, reports the Independent.

Writing in his acclaimed book Pity of War, Professor Ferguson wrote: “Though his work in the Treasury gratified his sense of self-importance, the war itself made Keynes deeply unhappy. Even his sex life went into a decline, perhaps because the boys he liked to pick up in London all joined up.”

Human rights campaigner Peter Tatchell condemned Ferguson for last week’s comments.

“I’m glad Ferguson has apologised for his homophobic slur against Keynes. However, it is shocking that such casual homophobia apparently exists in high academia. His remarks are what we might expect from a pub bigot, not from a Harvard history professor,” he said.

Stonewall Chief Executive Ben Summerskill questioned the apology made by Ferguson in a statement on his website at the weekend.

“Far from being off the cuff, he has been making these pretty offensive observations for some time. While on the face of it his apology is nice to read, it is not entirely clear whether the motivation is genuine regret or convenient,” he said.

“If he takes the view, and it now emerges he has expressed it in print, that gay people cannot have a proper sense of economics or history, can he offer some assurances that this has not affected his evaluation of students in the past?” he continued.

The 49-year-old history professor wrote an extensive apology last week after he suggested that the economist’s theories were wrong, because he had been in same-sex relationships, and therefore was too selfish to care for future generations.

Ferguson tweeted to apologise, and published a full apology on his website, after making comments on Thursday that famed economist John Maynard Keynes, and his economic theories, were inherently selfish because he was bi, married to a ballerina, and had no children.