A governor at the University of East London has resigned over the board's treatment of vice-chancellor Martin Everett.
Professor Everett has officially been on "indefinite leave" since 8 July, and no further details have been given to staff.
The University and College Union at UEL said in a circular to members last week: "Union officers have good reason to believe that the vice-chancellor is not on extended leave but has been suspended by the chair of governors following discussions that involved some deans and senior managers."
Governor Gillian Slater, former vice-chancellor at Bournemouth University, resigned earlier this month. She told Times Higher Education: "I resigned because I could not agree with a decision taken by the lay members, the path the board had decided to follow and the treatment of the vice-chancellor."
She added: "I know of no allegation of gross misconduct against the vice-chancellor. It may be that the issue is around the style of leadership." Professor Everett is understood to have a more consultative style than his predecessors.
The UCU memo said: "It is clear that the decision is being strongly contested and that it may result in considerable expense for the university. If the dispute is prolonged it is also likely to damage the institution's standing."
A senior source told Times Higher Education that Professor Everett had been suspended for "lack of leadership" and that there were no clear allegations against him.
A special committee has been set up by the board, as required when dismissal of the vice-chancellor is under consideration.
Times Higher Education understands that no university employees were present at a meeting of lay governors on 8 July which concluded with the decision to suspend Professor Everett. Staff and student governors were not told that the meeting was being held.
The matter has been referred by several members of staff to the Higher Education Funding Council for England. The university declined to comment.