Striking university staff are "angry" and "absolutely burnt out", a union official said as thousands walked out in a second day of strike action across Scotland.
Around 8,000 lecturers, librarians and researchers who are members of the University and College Union ( UCU ) continued their 48-hour walkout on Friday in an ongoing dispute over pay, pensions and conditions.
The UCU said many of its members are employed on precarious contracts which does not give them enough time for marking or supporting students.
The union also claims members have lost 35 per cent of their expected pension income after cuts were made to the Universities Superannuation Scheme (USS).
Speaking to BBC Radio Scotland's Good Morning Scotland programme, UCU Scotland's Mary Senior said staff are "burnt out" given their current conditions, adding: "Hundreds of university staff in Scotland are on short-term, fixed-term and hourly paid contracts.
"Their pay has lost value by 25 per cent since 2009. They are faced with unsafe workloads and precarious contracts in the sector. Those on hourly paid contracts aren't often paid for the time to mark essays or to provide the extra support students need. We really are in an unsustainable situation."
She claimed the pension scheme has a £1.8 billion surplus and cuts of more than a third have been made.
Senior added: "You can see why our members are so angry and that's why we had strong picket lines yesterday and we're expecting the same today."
Students will see disruption while strikes are ongoing as they gear up for exams and assessments in the coming weeks, but Ms Senior said the UCU has been "heartened" by the support it has received from students.
Speaking about the strike action, Senior said: "It's deeply regrettable, workers come into the university sector to support students, to provide them with education. We've been really heartened by students who have joined us on the picket lines. They know our working conditions are their learning conditions."
University staff had a 3 per cent pay offer "imposed" on them, Senior said, but she warned with inflation in double figures, that "doesn't cut it".
Employers say they are taking steps to mitigate disruption, adding the union is seeking an "unrealistic" 13.6 per cent pay rise which would cost institutions around £1.5 billion.
Professor Steve West, from Universities UK, said: "We're trying to do everything we can within the environments we're operating with the funding we've got to make sure we are fair and transparent in the way we support our staff. My number one priority at the moment is to ensure we don't disadvantage students.
"Frankly they've had a really difficult time over the last few years with Covid. This is the last thing they need."
Meanwhile, postal workers who are members of the Communication Workers Union (CWU) also walked out again on Friday in an increasingly bitter dispute over pay and conditions.
In an article for The Independent, CWU general secretary Dave Ward wrote: "The reason for today's strike is simple: it's about stopping the Uberisation of Royal Mail. The management agenda is about Royal Mail being transformed into a gig economy-style parcel courier, with a business model reliant on bogus self-employment and casual labour.
"For employers, the decent conditions and job protections our members enjoy seem to be a downside to running the company, which turned a £758 million profit last year. The other obstacle is the CWU, who they rightly see as a serious obstacle to this levelling-down agenda."
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