Cambridge University has been accused of "clamping down on protest" and curbing free speech following the punishment of a student.
English literature student Owen Holland was originally suspended from the university for seven terms after protesting during a speech given by higher education minister David Willets last year.
The Septemviri, an internal university court, has now cut the sentence to one term.
A spokesman for the university confirmed the reduction but said the court had upheld Mr Holland's conviction for "recklessly impeding freedom of speech".
But the campaign group Reinstate Owen Holland issued a statement describing the process as a "sham", adding it was in fact the university which had repressed freedom of expression.
Members called for reform of the university's internal disciplinary process, describing it as "antiquated and Byzantine".
Asa Odin Ekman, a graduate student, said: "The university is trying to appear magnanimous by giving a sentence which in any other circumstance would nonetheless appear absurdly Draconian.
"Owen has already suffered financially and personally from this needless punishment, which follows a pattern of clamping down on protests by real courts as well as this sham one."
The punishment came after Mr Holland read out a poem that disrupted a speech by the minister.
The poem included the lines: "You are a man who believes in the market and in the power of competition to drive up quality. But look to the world around you: your gods have failed."
The minister was forced to abandon the speech on the "Idea of a University" last November.
The Reinstate Owen Holland group said it would continue to protest against the ruling in the new academic year.
Speaking on behalf of campaigners, Dr Priya Gopal, lecturer of English, said: "While this is a welcome rejection of the absurd and unjust initial sentence of 2.5 years, it is a great shame that the university did not choose to uphold the right to protest that ought to be a fundamental to its ethos.
"The time has come to reform its antiquated and Byzantine judicial procedures towards greater accountability."