Reading University's ruling council has approved a controversial proposal to close its physics department in 2010.
Students protest at the decision to close Reading's physics department
Ahead of the meeting, the Institute of Physics had called on the university not to go ahead with the closure.
But the vice-chancellor, Prof Gordon Marshall, said higher costs meant it could not continue subsidising the loss-making physics department.
Reading's share of £75m to sustain departments until student demand picked up would not be enough, he said.
The money, from the Higher Education Funding Council for England (Hefce), involves £25m a year from 2007-08 to support courses in chemistry, physics and aspects of engineering.
In an open letter, Prof Marshall said the university's share of the extra funding from Hefce would, he believed, be some £180,000.
The university says physics facilities will continue to be used
That had to be set against a recurrent loss of more than £500,000 and the need to recruit a research team of three new posts with on-costs and equipment - a further £250,000 at least.
"I do not see that the modest share of new money that would come to the Reading department changes the funding landscape significantly."
He also highlighted the lack of demand for physics courses.
He said he had received letters of concern from schools and MPs - in areas which sent few if any physics students to his university.
"One such letter was forwarded by an MP for an East Anglian constituency, which had failed to send the university any physics students whatsoever during the past decade from its four schools and colleges," Prof Marshall said.
In a statement, the university said the ruling council had decided the department would close in 2010 as planned. Members voted 18 for the closure, five against, with one abstention.
The University and College Union (UCU) and students from Reading staged a protest, unfurling a giant petition against the closure.
UCU joint general secretary, Sally Hunt, said: "Over the past few weeks and months we have heard nothing but encouragement for science and innovation in the UK from all sides.
"However, warm words mean very little when scientists are being made redundant, labs are closing and courses are being axed, especially at a time when we need more, not fewer, scientists."
The prime minister had said science would be as important as stability for Britain's economic future - so urgent action was required.
The UCU published a report showing a 10% reduction in the number of core science and maths degrees offered by UK higher education institutions since 1998 - although biology provision had risen by 9%.
It said chemistry and physics had been worst hit.
Philip Diamond of the Institute of Physics said the decision was very disappointing.
But he added: "The institute is pleased that the government has now realised that there is a need for short term funding to support strategically important subjects such as physics at universities.
"This will give Hefce time to review the real costs of teaching across the higher education sector and provide the basis for a more realistic way to meet the high costs of the science and engineering subjects at universities."
Higher education minister Bill Rammell said Hefce had been asked to confirm measures to maintain provision of physics in south-east England but it was "in no-one's interests for the government to micro-manage which subjects are taught by universities".
He added: "It is important to see the position across the country. There is no room for complacency but science subjects are regaining popularity.
"Physics is taught as a major subject at some 50 UK institutions. Applications for physics were up 10% last year and the national demand for and supply of courses in many science-based strategic subjects is improving with student numbers rising faster than the national average."
Liberal Democrat education spokeswoman Sarah Teather said what had happened highlighted the vital importance of igniting an interest in science early on in education.
"It's a terrible cycle that must be broken. We need more science graduates as expert teachers in school to fuel demand in the next generation for science courses at university," she said.