Tens of thousands of university staff will go on strike for three days later this month.
More than 70,000 staff at 150 British universities will walk out in a dispute over pay, working conditions and pensions, the University and College Union (UCU) said.
The strikes, set to take place on November 24, 25 and 30 could impact up to 2.5 million students in what the union described as the biggest industrial action to ever hit the sector.
Disruption can be avoided, the union said, if employers make improved offers but warned that action will escalate in the new year.
They are also threatening a marking and assessment boycott if the dispute is not resolved.
Union members will also begin industrial action short of strike action from November 23, which includes working to rule, refusing to make up work lost as a result of strike action and refusing to cover for absent colleagues.
The strikes come after UCU members overwhelmingly voted in favour of industrial action last month in two national ballots over pay and working conditions as well as pensions.
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UCU general secretary Jo Grady said: “Campuses across the UK are about to experience strike action on a scale never seen before. 70,000 staff will walk out and make clear they refuse to accept falling pay, cuts to pensions and insecure employment.
“This is not a dispute about affordability – it is about choices. Vice-chancellors are choosing to pay themselves hundreds of thousands of pounds whilst forcing our members onto low paid and insecure contracts that leave some using foodbanks. They choose to hold billions in surpluses whilst slashing staff pensions.
“UCU members do not want to strike but are doing so to save the sector and win dignity at work. This dispute has the mass support of students because they know their learning conditions are our members’ working conditions.
“If university vice-chancellors don’t get serious, our message is simple – this bout of strike action will be just the beginning.”
The UCU is calling for a “meaningful” pay rise to deal with the cost-of-living crisis and an end the use of “insecure” contracts.
The union said employers imposed a 3% pay rise this year following more than a decade of below inflation pay awards.
Regarding the pension dispute, the UCU is demanding employers revoke a “package of cuts” made earlier this year which it claims will see the average union member lose 35% from their guaranteed future retirement income.