Six Oxford University students who object to tuition fees and have refused to pay them have been banned from lectures.
The students must pay up by the middle of February or risk flouting university residence regulations that could lead to them being blocked from sitting exams.
A university spokesman said: "There will come a point at which they will start to jeopardise their time at university."
Although they are still in college accommodation, the protesters could eventually face eviction if they break residency requirements, he added.
Kirsty McNeill, president of Oxford's student union, said: "The university is, in effect, bullying these students to an extraordinary degree. They are being very brave and principled."