There's a gap. Right there, by the end of the fence. I manage to squeeze through (just), followed by James and we stand on the other side for a moment letting our senses adjust a bit. Suddenly all the light has gone. I can feel bits of glass and corrugated iron and goodness knows what else under my feet but I can't see a thing. The tunnel is doing strange things to our voices, too. It's not an echo exactly, more a distortion so that whenever we say something a crowd of hidden onlookers seems to be whispering behind our backs. It's an unsettling place.

But this is the only way in, the only way to find what we're looking for, so we start to walk gingerly forward. James tells me to be careful because there are a couple of holes up ahead. After about two minutes, the darkness starts to dissipate and we can see the end of the tunnel; after about five minutes, we emerge into the hidden, subterranean place we have come to find.

A long time ago, this used to be a railway station. The platforms are still here, splattered with graffiti and pigeon dirt, so it's not hard to imagine commuters standing around waiting for the steam trains that would thunder through the tunnel we've just walked through. It hasn't been a station since 1939 but it doesn't look that old; the decay doesn't seem too extensive and parts of it are filled with light that pours enthusiastically in from several big gaps in the ceiling. We look up through the gaps and can see the tops of the trees and hear mothers pushing buggies and gossiping. They have no idea we're down here. How funny.

It's the Botanic Gardens up there of course. We are so close to the workers, joggers and students talking a short-cut through the gardens, yet most only have a half-idea that this old station is here. At least they did, until bar owner Stefan King decided he wanted to build a nightclub here.

Today, as we walk along the old platforms, James Connor and I have to admit it would make a rather brilliant nightclub. It's a dramatic and gothic space; imagine all those glazed tiles cleaned up and lit, a floor straddling the space between the platforms, music pumping. It's just as easy to imagine clubbers here as commuters.

James has another idea though, a rather more adventurous and exciting one. And we have walked through the tunnel to stand here and talk about what it could be like. "The café would be here," says James, pointing down through the platforms. "And the spiral staircase here." He walks a little further down the platform, broken glass breaking into even smaller pieces under his feet. "And here is where the stalls would be."

James gets more and more animated as he describes his plan. It's just a simple and zeitgeisty idea. No wonder it won the Eco Trust Prize for Emerging Talent last week and was shortlisted for this year's Design Medal, too. An eco centre. Brilliant. It would be for everyone who loves the environment, but would promote those who are trying to save it, too.

The site would be divided into distinct areas. One would be filled with stalls where producers could promote green products and services, another would house a book shop and deli, another a cafe selling locally produced food, maybe even grown in the botanics itself; in another zone, people could come just to meet and chat.

It would all feel like the park had come down to reclaim this space; in fact, James's plans feel like part of the botanics already.

It's hard not to buy into James's idea when you speak to him. He is a young, thinking designer from Leeds who came to Glasgow School of Art to train. For the past few years, part of him has been a student, part of him a dad to his three-year-old daughter, and part of him a dreamer who came up with the eco centre idea for his final project. "It's a design that developed from loads of projects I'd done previously and a lot of research I'd done into sustainable architecture and materials and design," says the 25-year-old.

"I was shocked when I read about how much brand-new building material goes to landfill every year."

And so he decided to do something about it. The green campaign needs to recruit lots of Jameses - twentysomethings who are already taking action.

James's horror at what he calls the "world wrapped in plastic" is genuine - he worries about people who buy sofas, and children's toys or dummies or food or even, he says with a Carry-On laugh, people who like wearing PVC trousers.

The central purpose of James's eco centre would be to educate those people. He is just out of full-time education himself, but here he is already eager to educate others. Finding out about being green is often about searching deep in Google, but James would make it much easier.

"My idea is to promote the ideas that are out there and people are developing," he says. "It's sometimes hard to get connected to the people who are trying their hardest to promote their ecological ideas. This would be a centre for people, businesses or anyone who wants to go and find out information; it's a learning space, an educational space. From day one, my idea was to have it as a constantly developing area."

I TRY to ignore the pigeons, empty wrappers and twisted metal and imagine how it would all look, imagine James's message getting through. And then something takes me back into the real world. Would this really work? The thing with Stefan King and his G1 group is they know how to make money. Clubbing + lots of beer + tickets = money.

Would an eco centre make any? "It would make more money than his plans," insists James. "This is going to attract people from all over Europe. I want this to be for everyone. The problem with nightclubs is they're fantastic when they're open and everyone wants to go, but in 10 years it'll be a dive."

James insists that his idea would not be exclusive, but inclusive - the space wouldn't just be for designers, or night-clubbers, it would be for everyone and in that sense it would continue the original Victorian philosophy which inspired those individuals behind Glasgow's parks.

What's marvellous though is that James's idea is now more than just an idea. When I watched him pick up the Eco Trust award last week, I could feel momentum starting to gather round it.

Martha Wardrop, the Green councillor for Hillhead and one of the leading campaigners against the nightclub plans, approached James after the awards to talk about his idea and now wants to explore how she could make it happen.

"It is an unused site so there's potential for innovative ideas," she says when I ask her about the plans. "I'm concerned about the environmental impact of any proposal for the site and would like to promote a high standard of design, using sustainable and recyclable materials.

"If this could be done as a community-led project, I would be supportive and there should certainly be a feasibility study on it. It would generate income from sales of products but any money should go back into the project and looking after the gardens. No individual should gain from it."

Wardrop starts to fizz when we talk about King. "There was never any indication that a nightclub would materialise there. There are other facilities in the area already; people can go drinking and dancing elsewhere.

"What we're lacking is quiet spaces, where people can spend time with family and friends. It's about working with people who already use the park."

James is excited and delighted at the support from Martha. "It's my design but I feel a bit powerless now. It's a nice design, but needs a lot of development. It needs the involvement of engineers and architects. But it could work."

It is, in other words, just the first small step. Who knows if it will go any further? Who knows if the nightclub will eventually be built here? Certainly, standing here in this old station, listening to the rainwater dripping and the pigeons flapping, I feel that something should be done.

This hidden place should be opened again so the walkers and workers and mothers with their children could come down those stairs again one day. This place could come alive. One day.

James Connor's Eco Design Centre plans are on display as part of the Design Medal exhibition at the Lighthouse in Glasgow until February 15, 2008.

Park Life
How do you get people to visit and use parks more without destroying what makes them attractive in the first place? Parks around the world have taken different approaches.

Vigeland Park, Oslo: The park spreads out over 80 acres and is covered with 212 sculptures by Gustav Vigeland.

Central Park, New York: The world-famous park (pictured) includes a carousel, ice rinks and the Boathouse Cafe where When Harry Met Sally was filmed.

St James's Park, London: Covering 58 acres, it has all the usual facilities of a British park but there is also an award-winning restaurant open throughout the year.

Prater Park, Vienna: Who needs the London Eye? This famous park houses the Resienrad ferris wheel built in 1897 and the star of The Third Man.

Tivoli Gardens, Copenhagen: This much-loved park is filled with buildings inspired by architecture from around the world and has several beer gardens and live music venues.