Knock, knock! Who’s there? Boris Johnson Oh God, what’s he done now? He has made another joke – hence my small but heartfelt homage above.

This time, it was at the launch of the World Islamic Economic Forum at City Hall, London. He was appearing with the Malaysian prime minister Najib Razak when Razak was asked about the role of women in Islamic societies. The prime minister replied that he had just learned that of ‘the latest university intake in Malaysia, a Muslim country, 68% will be women entering our universities.’ A moment of justifiable pride and an opportunity for reflection by representatives from less progressive countries was interrupted by Johnson announcing that the women were actually going to university because they ‘have got to find men to marry.’

Meanwhile, in America, a woman and Princeton graduate called Susan Patton was causing controversy with her article in her alma mater’s student newspaper that advised female undergraduates to ‘find a husband on campus, before you graduate.’ It was what she would tell her daughters [if she had them – she has two sons], she said. Why? Because, ‘Men regularly marry women who are younger, less educated… Smart women can’t (shouldn’t) marry men who aren’t at least their intellectual equal. As Princeton women, we have almost priced ourselves out of the market… you will never again be surrounded by this concentration of men who are worthy of you.’

Of the two manifestations of essentially the same belief – that the goal of any woman at university is not a degree but a suitable husband – it is actually the more flippant, Boris’ joke, that is most disturbing.

Patton, however misguided, is clearly sincere and wants to let others benefit from her life experiences. She was born in the Fifties, when ‘Mrs degrees’ (four years openly spent husband – rather than grade – hunting) were an acknowledged practice, and obviously shaped by that. Still, Patton may be wrong*, but she is not trying to be funny, she is trying to help.

Boris is trying to be funny. His defence since the story broke is that his remark was just a joke. Fine. What is a joke? At anything more sophisticated than the knock-knock level, a joke is essentially an unspoken truth being spoken. So the speaker needs to believe in the essential truth of what he’s saying. He also needs to think that it is a common enough belief that his audience will accept, understand and appreciate the taboo being broken and laugh with him as a reward for his insight and minor bravery in speaking out.

That’s a very technical way of putting it, and makes me sound slightly humourless, but it is the basic contract between any joke teller and his audience. In short, Boris is so sure that this is secretly what women are doing – AND that everyone secretly knows this – that he can risk lobbing his gag into a gathering of serious minds with serious purpose because the laugh is near-as-dammit certain.

Lucy Mangan: Female students want a degree, not a husband