Vaccine research to fight HIV, hepatitis C and parasitic infections will suffer after the plug was pulled on Europe's sole chimpanzee research facility.
The Biomedical Primate Research Centre in Rijswijk, Holland, will continue work on other primates. But the Dutch science minister's announcement that work on chimpanzees should cease disappointed British scientists involved in such experiments.
They predict the move will either halt projects or drive them to the United States.
Ronald Bontrop, director of the BPRC, which is funded by the Dutch government and the European Commission, defended the centre: "We do things very carefully here because there are no alternatives available and we have a lot of support from the scientific community."
While Home Office guidelines forbid licences to experiment on chimpanzees in the United Kingdom, some British scientists are involved through European collaborations including the BPRC.
One scientist, who wished to remain anonymous for fear of attack, said such experiments were vital in his field investigating vaccines against debilitating parasitic infections.
He is contemptuous of western protesters whose actions, he believes, hinder efforts to improve life in the developing world: "If you want to kick poor people in the teeth, this is the right way to do it."
Sir Walter Bodmer, vice-president of the Research Defence Society and principal of Hertford College, Oxford, described the decision as disturbing. While his work has not involved chimpanzees, Sir Walter's late wife, Julia, was involved in DNA analysis.
"There are some enormously valuable things that can be discovered by comparing modern humans with our nearest cousins," he said.
Protesters who have complained about conditions in the BPRC were jubilant. Jonathan Owen, spokesman for the World Society for the Protection of Animals, said: "The vast majority of the experiments are not necessary."