The national academic pay system faced potential collapse this week as Imperial College London prepared to announce its own, locally determined, salary structure.
Imperial will announce its new pay and job grading arrangements next week, although employers and trade unions are working on a deal around the national negotiating table.
Lecturers' unions feared the move could have a snowball effect, with top universities turning to the free market now that the government has opened the way for differential tuition fees.
Imperial would not discuss the plan in detail, but a spokeswoman said it was "modernising" its pay and grading structures as part of its human resources strategy, agreed with the Higher Education Funding Council for England, designed to recruit and retain top staff.
Rector Sir Richard Sykes is an advocate of the free market in higher education, floating plans for tuition fees of up to £15,000 well before the government announced proposals for £3,000 top-up fees.
He has unilaterally ignored the bottom two-thirds of the national lecturers' pay scale in order to pay staff an additional £8,000 a year, setting starting salaries at £28,000 and raising professors'
minimum pay from £39,000 to £42,000.
Malcolm Keight, assistant general secretary of the Association of University Teachers, said: "We're committed to national bargaining but we're not going to miss opportunities to promote the interests of our members. If the college can show people will be better off as a result of the proposed changes, we will be looking to speak to them about their ideas.
"The onus is on the college to prove this will happen. As yet, it hasn't shown us anything to indicate how this will affect salaries and job grading."
One union source said: "This is tough for the AUT. Its members at Imperial will get better pay from this local arrangement, as will AUT members in other top universities if they follow suit, but the union will not want to concede the fundamental principle of national bargaining."
Mike Sterling, vice-chancellor of Birmingham University and chair-elect of the Russell Group, said it was not an omen for all research-intensive institutions.
"The Russell Group does not have a policy position on national pay bargaining, as we are all waiting to see what the impact of the deregulation and the introduction of top-up fees in 2006 will be. But certainly Russell Group institutions will charge additional fees and will find themselves in a better position to pay. It is logical that differential pay structures may emerge after 2006."
Jocelyn Prudence, chief executive of the Universities and Colleges Employer's Association, which nationally negotiates on behalf of vice-chancellors, accepted that Imperial's move put pressure on Ucea and the system.
"We are now involved in intensive discussions with the unions to work out our framework document (on national pay scales and job grading) in time for the August 1 deadline. Perhaps Imperial might be interested in looking at the outcome of that.
"It is now even more important that we successfully conclude the negotiations this summer, or there will undoubtedly be more examples like Imperial that will push on and implement their own pay structures."