A new primate neuroscience laboratory based at Cambridge University has been granted a long-awaited go ahead from the government, but rising costs mean the project may never be realised.

The University is aiming to build a world-class primate neuroscience centre that would contribute to research on diseases like Alzheimer's, stroke and Parkinson's.

Concerns about animal right protestors targeting the site led the police to oppose the site's location on a main road and close to a motorway intersection, but a public inquiry held last year called for approval in Whitehall, which has now come three years after plans were submitted.

The centre has been strongly opposed by animal right's groups such as Animal Aid but has been welcomed by the medical research community. RDS, the UK body set up to promote understanding of the role of animal testing in medicines development said having a state-of-the-art centre was essential if the UK was to keep its position as a neuroscience research world leader.

But a £7 million shortfall in funding has already delayed the start of construction on the £30 million centre but the University Pro-Vice-Chancellor Tony Minson says its whole future remains in doubt.

"Unless we find a business plan that works, the project is at risk," he told the BBC.

He said a combination of inflation, and changes to the regulatory  and financial position of the University had led to a considerable increase in project costs.

"The University remains convinced of the national importance of this research to medical advancement," he added.

Andrew Tyler, director of animal right's campaigners Animal Aid commented on speculation that Cambridge could withdraw its plans, forcing the government to move primate study to its Porton Down military research centre.

"Cambridge is looking for a way out. If they take it to Porton Down it will compound the fact that this is grotesque and pointless research by making it secret and inaccessible as well. Wherever it goes, we will fight it."

The University has a Home Office licence for animal testing and all its animal research is subject to national peer review and a local ethical review process. It is also developing new techniques that could be used to replace animals in research, such as cell and tissue cultures and computer modelling.

Approval for the centre was welcomed by the ABPI, which said the decision was undoubtedly made in the best interests of patients.

Director general Dr Trevor Jones said: "It would have been quite wrong if research into how we can help these people was prevented through fear of what action animal extremists might take.

"This centre will provide a golden opportunity for the UK to keep world-class scientists and stay at the forefront of research in these areas."

Earlier this year a government advisory body concluded the pharma industry should do more to reduce the numbers of primates used in pre-clinical testing of new drugs.

The Animal Procedures Committee said scientific advances mean that pre-phase I trials of some drugs could now safely be conducted in humans, and should be encouraged.

Professor Colin Blakemore, chief executive of the Medical Research Council, said: "We know that many people find the use of primates in medical research distressing, but the Cambridge research facility is needed to enable scientists to find treatments for life threatening diseases.

"Studies involving primates have been crucial for our understanding of brain function, and have underpinned the development of brain scanning methods in humans.  They have also have led to important advances in the treatment of Parkinson's disease and strokes and current research is offering hope of treatment for Alzheimer's and Huntington's disease.

Testing on primates represents only a very small proportion of the total amount of animal research in the UK: less than 3,500 of the 2.7 million annual experiments are performed on monkeys, with the vast majority carried out on rodents