A university lecturers’ union has sanctioned 14 more potential strike days designed to hit the exam period after talks to resolve a pensions dispute broke up without resolution.
University and College Union (UCU) members are in their ninth day of action and will be on strike next week.
Sixty-five institutions could face more strike action unless an agreement is reached.
Universities UK said it was disappointed more action was planned.
Talks are due to resume on Friday.
The wave of strikes is designed to hit the exam and assessment periods between April and June, but the union said it would now gather information on when the action would be most effective at different universities.
UCU general secretary Sally Hunt said: “I want to stress that I consider all this a necessary precaution against the failure of talks to deliver an acceptable settlement.
“The union would prefer dialogue and I have given my personal commitment to Acas that UCU is serious about reaching an agreement.
“However, if talks fail, we are prepared to carry out the action in defence of our pensions.”
A Universities UK spokesperson said: “Both sides are currently engaged in serious and constructive talks at Acas.
“We are committed to seeking a viable, affordable and mutually acceptable solution to the current challenges facing USS pensions.
“UUK has again restated its request to the union that industrial action is suspended while talks at Acas continue.
“As part of any alternative proposal, we will expect that industrial action is suspended while UUK consults with all employers.”