The absurd contention that a man is unlikely to be gay if he is married was made in the letters column of The Oxford Times a while back by the radio personality Sandi Toksvig. I have good reason to remember this because her view was advanced in the course of an angry letter in which she was demanding that I be sacked – in the most caring way, no doubt, as Dame Edna Everidge, would say. Her intemperate outburst in September 2012, with my reply to it, continues to enjoy an afterlife on the Internet.

Sandi’s annoyance with me arose because I had discerned what seemed to be pretty obvious, if closeted, homosexual tendencies in the officer character in her two-man war drama Bully Boy, and said so in my review of it. The doyen of our profession, Michael Billington, found them too, and mentioned it in his notice of the play in the Guardian.

But Sandi complained in her letter that there was no gay streak whatsoever in her character. “Indeed the rather clear clue to his heterosexuality,” she wrote, “is when he talks about his wife.” (In the light of changes that have occurred since 2012, I should perhaps remind readers that in those days a wife was always female.) It is curious to find this strange statement being made by a woman with so much experience of the world, not to mention personal acquaintance with same-sex relationships, as her letter acknowledged.

Indeed, it was in consequence of her lesbianism, she claimed, that I had imagined the gay theme to her play. “Could it be that Mr Gray believes that a homosexual writer cannot help but infuse their characters with their own sexuality?” (It couldn’t, but let’s not go there.)

But Toksvig is not alone among intelligent people in believing that a married man is, ipso facto, not a gay one. A few days ago I came across the same idea being expressed by David Lodge, in his excellent new memoir, Quite a Good Time to Be Born (Harvill Secker, £25). (Lodge is coming to the Oxford Literary Festival later this month, and I am reading the book as a prelude to hearing him talk.) In discussing his time at a boys’ grammar school, Lodge describes his art master, Archie Brew. “[He] had a manner that I would later identify as ‘camp’.

“He called pupils by fanciful nicknames, pulled them by their ears or hair if they misbehaved, and threw tantrums of anger which might rapidly elide into peals of laughter. I knew nothing about homosexuality as a schoolboy, but retrospectively I was sure he must have been gay, as were other former pupils of St Joseph’s [sure, I think he means, rather than gay].”

Then Lodge reveals the evidence to disprove the theory.

“However, I discovered recently, after his death, that he was happily married with two daughters.”

A happy marriage, one feels, might not have been enough in itself to ‘prove’ Brew’s sexuality.

The children have obviously been mentioned to demonstrate his ability to ‘do the business’.

But, of course, marriage and children prove nothing. The Rt Rev Eryl Thomas, who resigned as Bishop of Llandaff 40 years ago after committing gross indecency, was a married father of four. His conviction and fine were big news at the time but now have been airbrushed from history.

One brief press report I found on the Internet came immediately beneath the news, on the same day, of Bay City Roller Les McKeown’s fine and three-months suspended jail sentence for an “unprovoked, violent and deliberate attack on members of the press” after a concert at Oxford’s New Theatre in the summer of 1975.

The victims were photographers Dave Hartley and Malcolm Rouse, formerly of The Oxford Times. I covered the case at Oxford Crown Court.

Even more philoprogenitive than the bishop was William Lygon, the 7th Earl Beauchamp, who had a notoriously active homosexual love life while fathering no fewer than seven children.

Many of them were friends of Evelyn Waugh, who was a regular guest at the family home of Madresfield Court in Worcestershire.

Lord Beauchamp supplied the model, in part, for Lord Marchmain in Waugh’s best-loved novel, Brideshead Revisited, being obliged, like the fictional figure, to live his life in exile. The earl was hounded from the country by the Duke of Westminster, the brother of his wife, who threatened to expose his illegal conduct. Ever after, the duke was inclined to refer to Beauchamp as “my b***er-in-law”.

The whole story is told in lurid and compelling detail by biographer Paula Byrne – in private (actually rather public) life Lady Bate, wife of Sir Jonathan Bate, Provost of Worcester College, Oxford – in her excellent book Mad World: Evelyn Waugh and the Secrets of Brideshead, which was published by Harper Press in 2009.

The book’s (very fruity) flavour may be gauged from the following passage: “Lord Beauchamp was said to have ‘exquisite taste in footmen’. When interviewing male staff he would pass his hands over their buttocks, making a similar hissing noise to that made by stable lads when rubbing their horses down.

If the young man was handsome and pleasant, Beauchamp would remark: ‘He’ll do very well. Very nice indeed!’ The fingers of the footmen of Madresfield were said to be glittering with diamonds. One could hear the clunk of the jewellery as they served dinner.”