Researchers in two subject areas funded by the Engineering and Physical Sciences Research Council have written to the prime minister to warn about the damage recent changes to the council's funding processes could do to their fields.
In July, the EPSRC announced its first decisions on whether to increase, maintain or reduce funding for the subjects in its portfolio as part of its efforts to "shape capability".
Among the subjects slated for reduction is synthetic organic chemistry. However, a group of nearly 30 researchers has written to David Cameron to warn that the cuts will undermine their work and "seriously injure an invaluable section of the UK economy".
The letter, organised by Anthony Barrett, professor of chemistry at Imperial College London, is backed by a statement of support signed by more than 100 scientists, including several Nobel prizewinners.
In response, David Delpy, chief executive of the EPSRC, has written to Professor Barrett to assure him that the cuts will be gradual and not "dramatic". His letter says the pressures on the EPSRC's budget mean a recent "spike" in funding for the discipline cannot be maintained without "damaging other important areas of the research base".
"I am sure that all of us would like to see the strongest possible UK research base...It is vital that we work together to achieve this and to demonstrate the importance of future funding for research," he says.
The EPSRC also announced last month that it is to merge its fellowship schemes and confine applications to priority areas.
Frank Kelly, chair of the Council for the Mathematical Sciences, has written to Mr Cameron to protest against the restriction of mathematics applications to researchers working in statistics and applied probability.
Professor Kelly, who is also professor of the mathematics of systems and master of Christ's College, Cambridge, says the changes have been introduced "with no warning" and would cut off one of the few sources of postdoctoral support in maths.
"Fellowships at the postdoctoral level provide a rare opportunity for the future leaders of the discipline to develop independently, and the loss of these fellowships to the general area of mathematical sciences will hit the best young mathematicians disproportionately," he writes.
A spokesman for the EPSRC said it would maintain overall funding levels for maths fellowships over the current spending period and intended to invite applications in more areas later this year.
But he noted that funding for statistics and applied probability had been highlighted as a priority in the recent EPSRC-commissioned International Review of Mathematical Sciences.
"The EPSRC did not support any postdoctoral research fellows in statistics and applied probability between 2005 and 2009. Focusing investment strategically in this area offers the chance to make a clear difference," he said.