Thousands of university students may not be able to graduate because of a pay dispute by lecturers, unions warn.
With no exams, no degrees?
Staff at some universities have refused to set exams and to mark course work; others plan to walk out altogether.
The vice chancellor of Essex University, Professor Sir Ivor Crewe, said it was "shameful" to harm students' employment prospects.
The National Union of Students said the students affected were very concerned about their futures.
The boycott by lecturers is part of national action by the Natfhe and AUT unions. They want a pay increase of 23% over three years; employers have offered 12.6%.
Sir Ivor said: "It is shameful and dishonourable for academics who are going on this form of strike to treat students who are an innocent party to this dispute in this way.
"It is going to do very real harm to students' employment prospects and I think it is an illegitimate way in which to carry out this dispute."
Sir Digby Jones, director general of the CBI, accused lecturers of ignoring students' needs.
"I cannot believe that the future of students across this country is being held to ransom in this way. A solution must be found before irreparable damage is done," he said.
Kat Fletcher, the NUS president, told BBC Five Live that the union had been putting pressure on both sides to resolve the dispute as quickly as possible.
"Sadly it's been going on for a really long time now and that's where the frustrations come.
"That's really because the university employers have been procrastinating about actually sitting down around the negotiation table and hopefully coming up with a mutually agreed solution."
AUT president Steve Wharton accused universities and colleges of ignoring a request to return to negotiations as the proposed deal was "not good enough".
Dr Gillian Howie, who has refused to set or mark any papers at Liverpool University since March, added: "You can just sense the absolute distress among our members that they're having to take this action but they feel they've absolutely no choice.
"It's a national scandal that institutions feel forced to respond in this sort of way, which is risking academic standards throughout the country."
Work is not being marked
Exams in Birmingham, Aberystwyth and Strathclyde have already been either cancelled or postponed.
In an escalation of the dispute, academics at Northumbria University voted to go on strike indefinitely after the university decided to stop paying about a dozen staff.
Branch chairman Martin Levy said other staff had been sent letters saying their pay would be stopped, starting from different dates.
He said formal notice of the proposed strike would be served to the university management on Monday. The start date was likely to be 23 May.
Northumbria University could not be contacted for comment.