Scientists are angry but animal rights campaigners jubilant after plans for a test centre using monkeys were axed.
Security is partly behind the decision to axe the lab
Animal rights campaigners welcomed the decision by Cambridge University to
drop proposals for its multi-million pound project in Girton, Cambridge.
But medical research expert Simon Festing said: "Patients with diseases such as Parkinson's and Alzheimer's disease will be the losers."
"Animal rights protesters have dealt a blow to UK medical research," he said.
The centre on greenbelt land at Girton was intended to draw in experts from around the world to carry out research into neurological conditions.
A Cambridge University spokeswoman said the decision to abandon the plans was taken because of the "financial risks" involved, including the costs of security at the complex.
The five-year planning period coincided with high-profile protests against experiments using animals at nearby Huntingdon Life Sciences.
Scientists fear the decision will cripple attempts in the UK to find cures for brain diseases.
Mark Matfield, director of the Research Defence Society, said: "This is a serious blow for British medical research.
"The government needs to bring in tougher legislation to tackle extremist campaigns, otherwise they will remain a threat to all medical science that depends on animal research."
Professor Colin Blakemore, chief executive of the Medical Research Council, said: "Studies involving primates have been crucial for our understanding of brain function.
"Current research in primates is offering hope of treatments for Alzheimer's, Parkinson's, Huntington's disease and strokes."
'Sordid and cruel'
He insisted experiments would still continue.
"We will try to make sure it goes on in Cambridge, but if not, it will go on elsewhere in the world."
But television writer and animal rights campaigner Carla Lane spoke of her delight at the decision.
"How pleased am I?" she said. "I can bear the thought of having Alzheimer's myself one day better than what happens to these animals. It's just awful."
Ms Lane, who wrote the hit BBC comedy series Bread and the sitcom Butterflies, branded the experiments "sordid and cruel" and warned that the announcement was not the end of the matter.
Wendy Higgins, campaigns director for the British Union for the Abolition of Vivisection, said: "The news is to be welcomed because it will save the lives of thousands of monkeys."
The RSPCA called for more research into alternatives to animal experimentation.
A spokeswoman said: "We need to move away from the use of these remarkable animals. This should not be beyond the bounds of scientific endeavour in the 21st Century."