The University and College Union says that it has been formally de-recognised at Nottingham Trent University and is threatening to take strike action.
The UCU and the university have failed to reach consensus over a new recognition agreement drawn up by university managers.
The agreement would have reduced the amount of time members of staff are allowed to spend on union duties by 80 per cent, the UCU said. It would also set up a new "Information and Consultation Forum", with a 50 per cent union membership, for negotiating pay and conditions, which the UCU said would marginalise trade unions.
On 4 July, Rachel Creamer, the human resources director at NTU, wrote to the union giving it notice of the termination of the current recognition agreement. Her letter notes that while the current agreement provides for nine months' notice of termination, because other unions, Unison and the GMB, had accepted that the new arrangements would commence on 1 October, "for practical purposes three months' notice is considered reasonable".
Ms Creamer said the termination of the agreement does not mean that the university is derecognising UCU. "The university will continue to recognise UCU on the same terms as it has previously, for consultation and negotiation, and collective bargaining purposes."
The UCU said that the termination in effect ended recognition. Sally Hunt, the union's general secretary, said: "The university can rest assured that it will feel the full force of the national union if it persists with trying to dictate the terms of the recognition agreement."
UCU branch secretary at NTU Colin Bryson, a principal lecturer in human resource management, said he had decided to leave the university, since his role as a union rep had become "extremely difficult". His decision came before the latest recognition problem.
A university spokeswoman said Dr Bryson had decided to go to another university, and it was not appropriate to comment. She insisted that the university would continue to comply with its statutory obligations to inform and consult the UCU.