Not many farms can offer two professors for a chat and still have a couple spare.

But then, this is not a typical Yorkshire farm.

It belongs to Leeds University, although you would not know that from its signage.

The anonymity did not stop saboteurs plucking 400 genetically modified (GM) potato plants out of the ground a few weeks ago. But normally, the farm gets on with its business unnoticed, up a quiet lane towards Tadcaster, while the world rumbles past along the A1 on one side and the A64 on another.

It is made up of three separate holdings – formerly a pig farm, dairy farm and arable spread. The pig business is still going strong but most of the rest of the land has been rented out since the university stopped teaching farming in the early 1970s, when a Labour Government was trimming budgets.

Its botanists, zoologists and ecologists still run studies there and there is steady work evaluating new strains of seed submitted for the approved list run by the National Institute of Agricultural Botany.

But even before the invasion of the eco-warriors, the university was thinking it could get more out of the land by building executive homes, and the future of all the farming operations is uncertain.

The discretion in not pinning down its location is a gesture. The potato saboteurs were assisted by a map reference from Defra which would have taken them to within a kilometre of the right field and the rules meant there could not be any more potato plants nearby. All they had to do was recognise the leaves.

The rule about publishing GM crop locations was meant to ensure that other growers could object if there was any threat to their own crops. In practice, it has meant GM experiments in Britain – in fact, in most of Europe – have become more or less impossible.

In the past three years, Defra has been asked for permits for just two experiments in the UK – the Leeds one, now abandoned, and one by chemistry company BASF, which is proceeding under guard in Cambridgeshire. Over the same period, the USA has approved probably a thousand.

Brazil is producing so much GM soya it is hard to buy a consignment which does not contain a bean or two of it.

Shippers are increasingly reluctant to deliver to Europe, because of the risk of being turned away. So European farmers are paying more for their pig and cattle food.

Half the world is using as much GM science as it can buy while the European Union is banning or stalling as much as it can get away with.

To some extent, the opposition has been proved right.

GM plants and nature's versions cannot simply live apart, side by side. Cross-fertilisation can be slowed but not stopped. The revolution has already happened.

Howard Atkinson, the professor behind the Leeds experiment, has been working on ways of reducing the damage caused by potato cyst nematodes without using powerful chemical sprays. Nematodes and the fungus known as blight mean potatoes need more spraying than almost any other crop.

BASF has found a way to splice blight resistance into potato genetics and Professor Atkinson has been working on one tweak which stops nematodes smelling the potatoes and another which stops them getting nourishment out of those they come across.

BASF is growing its GM potatoes under tight security in Cambridgeshire, after a first attempt was sabotaged last year. Prof Atkinson hoped to get away with a small trial on the university farm, which he has used before. In fact, he grew GM potatoes there from 1998 to 2002, when it was still possible to do these things unnoticed.

But he does most of his work indoors. Another professor, Tim Benton, researching the consequences for bio-diversity of different farming techniques, is farm manager Chris Wright's main customer from the university.

At 63, Prof Atkinson is about to start a three-year project teaching Ugandan scientists to inject his double-whammy protection into plantains (cooking bananas), which suffer even worse than potatoes from nematodes.

He said: "Somebody always says 'Ah, you're trying things out in Africa that you wouldn't do at home'. So I did particularly want this field experiment to go ahead first."

He was not particularly surprised when his seedlings were dug up, but he is determined that our Government – and Europe – cannot keep fudging the issue. He has suggested that if Defra wants the experiments, it should be prepared to host them, in secure fields.

"If we get a better policy out of it, I will feel the trashing of our plants was worthwhile. The trouble with the whole European precautionary policy on GM is that was switched on but nobody ever said when it would be switched off."

Prof Atkinson understands the reservations. His problem is with a hostility which makes no distinction between uncontrolled commercial growing and his small experiments, with potatoes and bananas, which are highly unlikely to lead to unwanted "escapes", because of the nature of the plants involved.

He added that a serious misunderstanding of the pollination process came into the arguments against a BASF experiment which was proposed (but eventually withdrawn) for East Yorkshire last year.

But it is not a logical debate, of course. It is a collision between futurists who think we have to choose between GM and chemicals and anti-industrialists who want all farming to be "organic".

Prof Atkinson says: "It's not within my expertise to say whether organic farming could feed the world. But I would think not. Potato farming is an interesting example. Organic growing takes place in an environment in which all the other potato fields are kept clean by artificial methods. I don't know if it would be possible otherwise."

At the National Pig Development Centre, Helen Miller, professor of pig science, is more forthright. The organic movement, or, at least, its political success, drives her potty.

"I don't see how going back to a system that didn't produce enough food before is going to work now. We have never been hungry so we don't realise how incredibly lucky we are," she said.

Her unit works for Leeds and Newcastle universities and Government vets, but mainly for the pig industry, which pays for experiments with feed and breeding, additives and immunisation, to try to shave pennies off the cost of a finished pig.

It is a market in which Hugh Fearnley-Whittingstall and his free-range Old Spot chops are irrelevant. Almost every country wants to export pig meat and most have looser rules than ours. The Danes have a surplus on their hands because America has nabbed some big Chinese contracts.

Professor Miller's sympathies are with anyone trying to make a living in the middle of it all: "We're normally self-financing but the university had to bail me out last year because of the price of grain."

With the help of two farm staff and four research students at a time, she runs 230 breeding sows and their offspring through to finish, incorporating the trials into the business.

"I love pigs. Most of them, anyway. They are such characters you can equally well dislike one. When people ask me about the smell, I say it fills me with happiness."

GM is not yet an issue in the pigs business but the day is coming. And Prof Miller, 51, will be open to anything which might cut losses from disease.

"It annoys me when organic farmers make a big virtue out of not using medicines. Is that being kind to animals, not to treat them when they are ill? It's like parents avoiding the measles jab. It only works if everybody else vaccinates," she said.