“We never know when some inconspicuous spark of knowledge may suddenly light up the road for the whole of society, without society ever realising perhaps how it came to see the road. But that is far from the whole story. Even those other innumerable flashes of knowledge that never illuminate the path ahead…have their deep social importance if only through the mere fact that they happened; that they might have shed light.”

What Gustáv Husák, then ruler of Communist Czechoslovakia, made of this 1975 letter from the incarcerated Václav Havel is a matter of speculation. But within 15 years, Havel was president of a post-Communist Czechoslovakia and Husák was history. Profound advocacy of freedom of speech does not always reap such rewards; it is satisfying when it does.

In the UK, it is too easy to forget just how fundamental freedom of speech is to a flourishing society. Perhaps we have come to take it for granted. When Jo Johnson, the minister for universities and science, raised it recently some suggested that it was a mere “gimmick”.

As Anthony Gottlieb points out in his wonderful book The Dream of Enlightenment: The Rise of Modern Philosophy, the philosopher Spinoza turned down a professorship at Heidelberg in 1673 because a condition of the role was that he not “disturb the publicly established religion”. Spinoza argued that intellectual freedom was “absolutely necessary for progress in science and the liberal arts” because those pursuing such activities needed to be able to exercise judgement “free and unhampered”.

The UK is blessed with a diverse array of wonderful higher education institutions – everything from world-leading research-intensives to teaching-led institutions at the heart of regional economies and small conservatoires at the forefront of performing arts. These institutions are united by that single profound idea that Spinoza was among the first to spell out: places of learning depend on freedom of thought and speech. Diversity of view is vital. And the key to genuine disagreement is that everyone involved seeks to understand fully the others’ case. Our economy depends on this, as do our culture and society. We cannot accept any compromise.

Maybe all this is obvious. After all, when I visit universities in my role as chair of the Office for Students, I meet wonderful people. I find students willing to speak up boldly about changes they would like to see in their institutions. This generation of students is demonstrably the best educated in history: hard-working, thoughtful, curious and ambitious. I feel a surge of optimism whenever I spend time with them.

Then, just occasionally, I read or hear something that suggests a potential threat to the freedom of speech that underpins such optimism. Here’s one example. On 2 November, Times Higher Education highlighted the Daily Mail’s attack on academics accused of being biased against Brexit. One of the examples highlighted by the newspaper was the academic who told his students: “We flourish because we are an inclusive and outward-looking community.” So far, so good. But THE concludes that the OfS’s proposed freedom of speech principle “is likely to diminish the number of academics willing to say such things out loud”.

On what foundation is this assertion based? We would never seek to limit any academic who wanted to make the case for or against Brexit or anything else. We will stand for the widest possible definition of freedom of speech: namely, anything within the law. Every institution should, too. Ideally, we will never have to intervene, but if we do, it will be to widen freedom of speech rather than restrict it.

Here’s another example. A well-informed student I spoke to agreed that freedom of speech was important but added that it might need to be limited in relation to questions of identity because otherwise it might make some people feel “uncomfortable”. But “comfortable” is the start of a slippery slope towards “complacent” or “self-satisfied”. And doesn’t much of the most profound learning require discomfort? As an undergraduate, I remember reading The Theory of Possessive Individualism by C. B. Macpherson until my head hurt. Definitely uncomfortable. Then the penny dropped and I felt the joy (not the fun) of learning.

Admittedly, this had nothing to do with my identity. So let’s take my Pakistani friend who, as a result of sheer hard work, found his way to a top US university. There, he enrolled in a comparative religion class and suddenly found himself faced with questions that challenged his religion, culture, upbringing and, yes, identity. “Uncomfortable” for sure. And life-changing.

To avoid discomfort is to retreat from freedom of speech: to run away from the good, the true and the beautiful. Instead, universities must help students develop the resilience and character needed to live with and benefit from being challenged.

What individual students or academics do when faced with the choice between “comfortable” and “uncomfortable” is a matter for them. But what institutions and regulators do is profoundly important. If they don’t err on the side of “uncomfortable”, they risk extinguishing Havel’s precious sparks of knowledge.

As they say these days: “Are you comfortable with that?” I hope not.

Sir Michael Barber is chair of the Office for Students.