The Association of University Teachers predicted a major shutdown during a four-day boycott by admissions tutors, and warned that the industrial action would escalate in the autumn to disrupt offers for next year's entrants if vice-chancellors did not improve their pay offer.
The action will start with a two-day boycott on Monday and Tuesday, timed to disrupt admissions in the wake of tomorrow's Scottish Higher results. A second two-day boycott is planned for 19 and 20 August the first two days of clearing after A-level results are published.
Staff who take part will refuse to deal with admissions queries during the boycott and will not process applications from students who have missed their grades. Students who gain the grades required to meet conditional offers will not be affected.
Disruption will be limited to the "old" universities. Staff in the former polytechnics are not part of the dispute and will work normally.
The real impact of the boycott is unpredictable but is potentially disruptive for students at a traditionally stressful time.
Admissions officials, universities and student leaders appealed to applicants who narrowly miss the grades they require to stay calm, take stock and wait if they cannot contact admissions officers during the boycott. Tony Higgins, chief executive of the Universities and Colleges Admissions Service, said: "We are not sure how solid the strike action will be and there will be those staff who are non-academics who will doubtless pick up the telephone and give students advice.
"The majority of decisions will be made prior to the strike action so the message is do not panic. It could be of considerable benefit because we like people to be calm and to take stock."
David Triesman, the AUT general secretary, predicted strong support from staff for the action, in support of a 10 per cent pay claim. He warned that admissions officers would delay the admissions process during the boycott, but insisted the system would return to normal.
He said the boycott would fire a warning shot to vice-chancellors, who have refused to improve their 3.5 per cent pay offer, and insisted the aim was not to harm students.
Mr Triesman said: "We are not intending to draw a lot of blood, but we will have demonstrated that the system is absolutely dependent on the goodwill of staff."
He warned that further action to disrupt next year's admissions cycle had not been ruled out. "We will analyse every aspect of the admissions process and we will pick what we think are the weak links in the chain," he said.
Peter Humphries, chief executive of the Universities and Colleges Employers' Association, insisted that the pay offer was the maximum possible, and said it had already been accepted by all support staff unions.
He said: "We regret any action that is taken and hope that it will not have any damaging effects on university applicants."
The National Union of Students, which has come out in support of the action, appealed to students to stay calm.
Andrew Pakes, NUS president, said: "The AUT has been forced by the employers into this situation. They are trying to hit university administrators rather than students. If students have not got their grades they need to consider their options calmly."Reuse content