One of the country's top universities is planning to cut up to 171 mainly academic jobs to make cost savings and ensure its "financial sustainability."
Manchester University said it proposed to open a voluntary severance scheme for staff at risk, to avoid the need for compulsory redundancy if possible.
The University and College Union (UCU) said there was no economic rationale for cuts on such an "enormous" scale.
A spokesman for the university said: "The University of Manchester has a bold ambition to be a world leading institution, with a reputation based on academic excellence.
"In order to meet this ambition, we must improve the quality of our research and student experience in some areas and ensure the financial sustainability of the University.
"Realising this ambition will require a capacity to invest in our strategic priorities.
"We have detailed plans for significant growth in funds from a range of activities, but we will also need to make cost savings.
"The Board of Governors has approved proposals from the senior staff of the university to commence consultation with the trade unions in relation to reductions of up to 171 posts."
The UCU said the cuts will hit 140 academic posts and 31 support jobs such as administration, concentrated in three departments - the School of Arts, Languages and Cultures; the Faculty of Biology, Medicine and Health; and the Alliance Manchester Business School.
The union said the university was blaming new Government legislation and Brexit as major threats to its future income.
UCU general secretary Sally Hunt said: "We see no economic rationale for jobs cuts on such an enormous scale.
"The University of Manchester is in a strong financial position and we believe it is using recent Government policy changes and Brexit as an excuse to make short-term cuts that will cause long-term damage.
"It takes a lot longer to rebuild a department than it does to dismantle one.
"If the university wishes to maintain its position as one of our leading institutions, it needs to rethink plans to sack large numbers of professors, lecturers and support staff."
A Unison spokesman said the union was "deeply disappointed" at the announcement, adding: "This follows on from reductions in the last two years of staff in IT services and catering and the university now appears to have an annual cuts programme across campus.
"The reduction in numbers of students to help the university's misplaced chase of league tables and savings can only damage quality and accessible education for all."