Universities across the country have lobbied education secretary Charles Clarke to move to save academic physics research.
The Institute of Physics and the heads of 37 physics departments wrote to Mr Clarke last week, warning that physics is under threat in the wake of the publication of the government's higher education white paper.
The letter follows government figures, revealed in The THES , showing that 79 university science departments, including 14 physics departments, closed between 1994 and 2000.
The IOP says the situation is even graver than the statistics suggest.
According to its calculations, 28 universities have dropped their physics degrees since 1994. There are now only 51 physics degree courses in the UK.
In the letter, Peter Main, director of education and science at the IOP, says: "By the time the new research assessment exercise is in place it may be too late to prevent a number of physics departments from closing.
The position of grade 3a departments, of which there are a few, is even more precarious."
John Davies, head of the 4-rated physics department at the University of Bath, said: "One of the difficulties is that we feel we have entered a competition where the rules have been changed after the game has been played."
But the IOP letter stresses that even the top-graded departments are experiencing difficulties and face tough decisions about which permanent staff they can retain.
The letter was signed by 19 heads of 5 or 5*-rated physics departments.
The Commons science and technology select committee is keen to act on these fears. Members of the committee are calling for a full inquiry into the state of science in universities. They plan to update the Department for Education and Science figures by asking all universities how many science departments have closed or merged in recent years.
Brian Iddon, a member of the committee, said: "Science is really suffering.
We are in dire straits."