A simple planning issue, or a turning point in the ethics of animal research?

"Cambridge is a wonderful place to come and have a demonstration," said Reverend Dharmavidya, a friendly, beaming bear of a man among several other Buddhists watching proceedings yesterday in a Cambridge council chamber. "Because if you want to bring attention to an issue, you want to do it in a place where there's plenty of people watching."

The issue to which he was referring to was a formal planning review of an application by Cambridge University to redevelop 307 Huntingdon Road, at present a collection of farm buildings on a trunk road in the west of the city. It might sound dull but the reality certainly is not.

The university wants to establish a laboratory complex for research on certain primates, most likely marmosets and macaques, which are among our closest living relatives in the animal kingdom. To understand neurological disorders such as Alzheimer's and Parkinson's, scientists want to examine brain function, which inevitably involves vivisection.

The plans have inflamed the sensibilities of animal rights protesters and brought into the open the conflict between them and the scientists who believe such research is essential. Politicians often talk about "having a proper debate"on issues such as genetically modified food and crops, embryology, and animal rights. You might wonder quite where the debate is meant to take place and reach a resolution. The answer is: in places like Cambridge's anonymous council offices, with its Identikit tables and chairs. When it comes to deciding our society's ethos, this is what Americans would call the place where the rubber hits the road.

And it is done through, of all things, the planning laws, which decide issues such as road, town and city planning, mobile phone use, and airport expansion, equally hot topics.

Here, the focus is on animals and the vivisection proposal. "It hits a raw nerve with us, and for many other religious communities," said Dharmavidya (formerly known as David Brazier), who has travelled down from Leicester where he lives in a Buddhist commune. "It moves the boundary closer to experimenting on humans. And we don't draw a hard line between human life and the rest of creation. This shifts the ethical boundary in the wrong direction." He was hoping his willingness to protest might mean he was called as a witness by South Cambridgeshire District Council, which is opposing the application. Not on any ethical grounds (the council insists it is agnostic on this), but because police believe the inevitable animal rights protests surrounding the centre would disrupt traffic and endanger protesters and drivers. The council also fears that such protests could harm the city's valuable tourist trade.

The protests would also clog the city centre where someone dawdling on a zebra crossing can briefly induce gridlock.

The university is pushing hard for the redevelopment of the site, which would accommodate a 10,000sq m laboratory. It insists the work is important, and in the national interest. It is supported by by Lord Sainsbury of Turville, the Science minister, who said the centre was "doing major research in a key area of science". He added: "I think it is very important that this research is done. It also happens to be done by probably the best people in this country to do it."

Its lawyer at the inquiry, Robin Purchas QC, suggested in his opening remarks that beginning primate experiments at the site would not entail a change of use. The site, he said, had been used for animal research "since the early Fifties". This nonplussed the university's spokeswoman, who said that "it hasn't been used for a year; before that, it was just offices".

It doesn't look like offices; or anything much. As you drive west out of Cambridge, you pass a farm – operated by the university – then a collection of farm-like constructions, in ageing brown buildings. That is 307 Huntingdon Road; and that, said the first witness to give evidence yesterday, Chief Inspector Robin Pearl of South Cambridgeshire police, would become the focus of anti-animal experimentation protests.

Two sets of solicitors are representing various animal rights groups, and also oppose the application. Yet the rules of this debate mean they are constrained in what they can object to.

It is not sufficient, beneath the gaze of Stuart Nixon, who is chairing the review, to say that vivisection is morally repugnant. Planning regulations do not recognise repugnance. So Animal Aid and the British Union Against Vivisection chose yesterday to argue the merits of the green belt, within which the buildings lie, pointing out that it was up to the university to demonstrate that its planned redevelopment was of such overriding national interest that it justified a new, gleaming building easily visible from the M11 motorway a mile away.

But Animal Aid also intends to call evidence that the research is unnecessary. Ray Greek, president of Americans For Medical Advancement, will be called as a witness by a coalition including Animal Aid. He says his organisation cuts across pro and anti in the animal rights groups; it just wants results humans can use.

"We're in favour of stem cells, for example," he says. But animal testing, he thinks, is outdated. "In the 1800s or 1900s, you could pretty much cut animals up as you wanted. But now the things we can do with functional magnetic resonance imaging means today we can do a lot of things to intact humans that we have been doing on open monkey brains. We don't want this [centre] to happen for a number of reasons; we think it's a waste of time and money."

The university says the centre is "vitally important for research into devastating and life-threatening diseases"and that "studying health and disease in animals is sometimes the only way to answer critical questions in medical research and has led to the development of effective treatments for conditions such as polio, diabetes and heart failure".

It adds: "We understand many people find the use of monkeys in medical research distressing. Research methods are continually evolving and while scientists and medical researchers aim to reduce work involving animals to a minimum, some of this work must continue if we are to make essential life-saving advances in medicine." The research, if it does go ahead, would be regulated by the Home Office's increasingly tight vivisection regulations.

The protesters have already won a minor victory through attrition. The university first applied for the expansion in 2000. That was rejected in January 2001, but resubmitted in August 2001, and heard by the council in February 2002. The appeal against it was lodged in May. And now it has come to a hearing, which will probably occupy seven days of the public forum, followed by a period of consideration by Mr Nixon.

But since that first application, the rise of animal protests not far from Cambridge, at Huntingdon Life Sciences' offices, have made the police and the council increasingly nervous. Chief Inspector Pearl said the university was already the target of animal rights protests, and that a protest group called XCAPE – Cambridge Against Primate Experiments – had sprung up.

He told the review: "While we will do our utmost to provide policing, there will be mass protests and direct action protests by the more extreme elements of the animal rights movement." He said a protester at Huntingdon Life Sciences had dug a tunnel near its perimeter and chained herself to a safe inside it. The company spent more than £250,000 getting her out.

His best suggestion? If 307 Huntingdon Road gets permission for the change, the university should dig a huge trench around its perimeter to stop people trying to break in.

But even if they do, that will not stop people like Reverend Dharmavidya from sitting down in the middle of Cambridge's busy streets. "This has a religious element to it, and wherever religion is involved then the protests are two times bigger," he said. "Just look at what happened in Nigeria. Religious issues play big."