The minister had scarcely stood up before the shouting began. "Dear David Willetts" announced a student protester, at the top of his voice, as he began to declaim a lengthy prepared statement. His every sentence was repeated by a chorus of fellow enragés seated strategically throughout the hall. There were three of them sat behind me, all shouting at the top of their voices. It was a decidedly uncomfortable experience.
Initial amusement at the unexpected interruption turned to annoyance and then exasperation as the protesters (who called themselves Cambridge Defend Education) droned on and on. Their "epistle" was low on facts and heavy on pretentious verbiage and painfully mixed metaphors. Its theme was the opposition between genuine knowledge and the marketplace -- "you cannot quantify knowledge" -- something that would have made a good subject for debate after Willetts had finished speaking. But there was to be no debate. Instead, rant (for the time being) over the protesters started up a shout of "Willetts Out!" and occupied the stage.
A few minutes later, the chairman Professor Simon Goldhill -- who appeared completely wrong-footed by the turn of events -- announced that the lecture was cancelled and that David Willetts had left the building.
Introducing the lecture, part of a series on the theme of "the idea of a university" organised by Cambridge University's Centre for Research in the Arts, Social Sciences and Humanities, Professor Goldhill had stressed that it was to be a robust exchange of views. "Things will be said on both sides that will be difficult to hear," he predicted. After a fairly short address by Willetts there would have been a longer question-and-answer session at which the minister's thoughts would surely have been subjected to intense scrutiny by students and academics in the audience.
It's unlikely that minds would have been changed in the process. Government policy is not made in public meetings. But the event nevertheless represented a valuable opportunity to examine the consequences of the planned changes to university funding and student finance. As a recent Guardian profile  by Decca Aitkenhead suggested, Willetts is a politician with a genuine (and sadly rare) passion for intellectual debate. In an era when most political events are phoney, stage-managed affairs with hand-picked audiences and pre-arranged questions, here was a minister willing to take part in a live, unpredictable and well-informed public meeting. Even if you disagree with his policies, this is surely something to be welcomed.
Instead we were subjected to a tedious monologue by a bunch of self-satisfied protesters unwilling to listen to any point of view other than their own. A supporter of the protest, Lawrence Dunn, said afterwards  that beause the government had ignored previous protests "it was therefore time to ignore what Willetts had to say". He is of course at liberty to ignore Willetts. But the people who were ignored last night were the majority of the audience who had come to listen to -- and challenge -- the minister. Their views and wishes were swept aside by the actions of an immature and intolerant minority. No doubt they genuinely care about education. But they appear to have no understanding of or interest in the process of democratic debate.
I contacted Professor Goldhill afterwards for a comment. He told me that while protests had been expected, no one anticipated that the lecture would have to be abandoned, something that "did not happen even in 1968". He regarded the events of last night as "an extraordinary opportunity missed" -- an opportunity for many of Willetts' "most articulate critics" to challenge him directly. He also described the form that the protest took as "an absolute abuse of the freedom of the university".
The university is nothing if not a place for the free and frank exchange of critical ideas. This was an attempt to stop the exchange of ideas, and was done against the overwhelming wish of the majority of people in the hall. It was made in the name of the values of the university, but distorted and destroyed those values. It was politically not just misguided by giving all the strong lines to Willetts, but the sort of totalitarian behaviour that we all should hate. In the name of giving voice to their so-called non hierarchical and open views they refused to let anyone who disagreed with them speak. You cannot shag for chastity.
Of course Goldhill is right, as is Cambridge Students' Union president Gerard Tully who released a statement  accusing the protesters of violating "one of the founding principles of University education", that of freedom of expression. It was not Mr Willetts' freedom of expression which was pointlessly disrupted last night: he is, after all, not short of platforms on which to speak. Rather it was the freedom of everyone in the audience who had their own questions to ask him or who were interested in what he had to say.
It was a sad day for Cambridge and for the principle of peaceful protest, which in a democratic society we all rightly value.