Relations between Northern Ireland's higher and further education minister Sean Farren and his Stormont scrutiny committee collapsed over student fees, a report has claimed.
Research by the constitution unit at University College London and the Belfast-based think-tank Democratic Dialogue has called into question the long-term democratic viability of the structures of government brought into being by the Good Friday Agreement.
The report, A Democratic Design , said that when the power-sharing executive broadly supported a policy of "no fees" linked to a high threshold for repayment of loans, Dr Farren attempted to disregard the executive's viewpoint.
Authors Rick Wilford, reader in politics at Queen's University, and Robin Wilson, director of Democratic Dialogue, said the report showed ministers could and had overriden committee and assembly votes "with apparent impunity".