Debbie Simmons has seen the future and it is filthy, unless she and her 800 child delegates can get their hands on it. Later this month, they fly in from all over the world to a conference in Eastbourne. She will be chairing it. She is 13 years old. Jessica Berens reports. Photographs by Julian Anderson
On 23 October, 800 children aged between ten and 12 will travel from more than 50 countries to stay in hotels along the seafront at Eastbourne. They will assemble at the Devonshire Park Centre where they will present projects on the environment and formulate a charter to take back to their respective governments.

Delegates include Dominique Godino from the Philippines who has seen the waterfalls of Hinulugang Taktak ruined by refuse and who is spearheading a campaign to rehabilitate the area; Sulmaan Khan, from Pakistan, illuminating the plight of endangered wildlife, in particular the houbbara bustard, the snow leopard and the Himalayan brown bear; and Ibrahim Alex Bangura, from Sierra Leone, who, through Peace Child International, has planted ten thousand trees in areas eroded by deforestation. Things have come a long way since recycling meant making models of Dougal out of old Fairy Liquid bottles, the days when a "meeting" was an egg sandwich in a tent in the garden.

The International Children's Conference on the Environment - with its slogan leave it to us - is the first of its kind, inspired by children, run for children and with the key decision-making remaining in the hands of children. Workshops, to be held in the afternoons, offer a sophisticated range. Subjects include the Internet ("discover the potential of global communication"), conference radio ("learn how to use the media to communicate your ideas"), and enviroscoping, DNA fingerprinting and biodiversity.

The driving force behind it all is Debbie Simmons, a 13-year-old British girl. Debbie, despite her wide, disarming smile and her dynamic plans for world improvement, is not the sinister dwarf of Hollywood lore. At home, she has a collection of carved owls, and is saving up to buy a flute. She is "not good at PE". She used to be quite shy. When she first joined the junior board of Drusillas Park - a private zoo near Eastbourne - at the age of eight, she "found it difficult to speak out". Now, as chairperson of the International Children's Conference on the Environment, she has found herself with responsibilities.

Meetings of the junior board are held at Drusillas Park on Saturday afternoons. Once in the boardroom, Debbie becomes a focussed individual with a bulging A4 folder and a firm and articulate manner. Pavel, who is from Russia, is 12 and has run in straight from school. Rebecca, 12, and Anna, 11, both have bobs and are business-like; Ben, 11, is quiet; Dermot, 12, is absent because he is at a Liverpool match. "Dermot's favourite word is 'patronising'," Debbie tells me before the meeting. "He doesn't like children's presenters because they are patronising."

Michael Ann and his wife, Kitty, both directors of the zoo, have always felt that, since children are their main customers, it is children who are likely to have the most pertinent ideas about the zoo. The junior board, launched in 1989, began by initiating schemes for the zoo - dustbins in the shape of animals, a play area for toddlers - but raised the idea of an international conference on the environment three years ago. A second group of children was then selected to organise the conference after letters were sent to local schools asking teachers to nominate candidates. Debbie, as a long-term member of the original junior board, was co-opted as chairperson. "The children felt that there was so much more that they could be doing," says Kitty Ann, "all they needed was a voice and some encouragement."

The project has involved argument, compromise, patience, endless telephone calls, faxes and letters, long days for the Anns (who organised backing and sponsorship) and stalwart commitment from Debbie and her team who meet twice a month. Finance has been provided by British Airways (who, acting as sponsors, are giving free flights to delegates - 600 of whom are from overseas) as well as organisations such as East Sussex County Council, Eastbourne Borough Council, the English Tourist Board and the United Nations Environment Programme. Delegates will pay a fee of pounds 94 and for their accommodation (at subsidised rates); most have been sponsored by their schools and local environmental organisations. A number of the children will present projects, chosen after hundreds of applications were examined by a conference sub-committee and the junior board, whose brief was to find interesting ideas from a wide geographical spread.

Thus the junior board has learned much of the specifics involved in the democratic process (the importance of voting, for instance) and Debbie can claim a working knowledge of how power works. The adults, meanwhile, may be credited with helping to realise what is, in essence, a child's fantasy.

"If you have one person saying 'I think you should do this', no one is going to take any notice," says Debbie. "But if you have 800 children standing there saying 'We think you should do this because you are ruining the world', then governments and the media might listen." She hopes that the event will "make people aware that children know what is going on".

Debbie is most reluctant to see herself as a heroine. Does she feel proud? "Yes," she says, "in a way. You come up with a small idea and it grows ... But it wasn't actually me, it was the whole board." She is not precocious or bossy, feeling only "a bit annoyed" when she sees someone dropping litter in the street. She would not dream of accosting the offender. "Even if you did", she says, "it wouldn't make any difference."

Debbie was born in Eastbourne. Her father, Anthony, is a solicitor and her mother, Joanne, an occupational therapist. The family live in a street full of gabled mock-Tudor houses. Debbie remembers a time when their garden stretched into fields in which there were sheep. Now there is a main road. The reduction of space is a tangible experience; a generation has grown up with a deterioration from which it has been impossible to escape. "The world", she says simply, "is turning into a tip."

Debbie's mother had watched Blue Peter as a child and had saved milk bottle tops for Guide Dogs for the Blind, a task familiar to anyone who grew up with John Noakes and his nice dog, Shep. "I don't throw things away," she says. "I just never have. But it was from the children that we got the recycling. Boxes go to the school; tin cans go to Drusillas for the rainforest." She had been a Girl Guide and, as a mother, took Debbie and her younger sister, Emma, on the pond-dipping expeditions that she had enjoyed when young. These helped to foster Debbie's love of animals and concern for their welfare, as did the school plays in which Debbie took part. The Bumble Snouts featured aliens who appeared on earth and were horrified by what they saw. In Ocean World, which addressed the endangerment of whales, she played the part of a coral reef, wearing a white catsuit decorated with fabric paints; and at ten, she appeared in Save the Human, in which society was run by animals and the humans faced extinction. These, she says, "made us more aware".

Joanne worries sometimes that Debbie will be agitated by the pressures of the limelight but thinks that, in general, she copes very well. "She knows I am here, but it is her thing and I let her do it."

The junior board settles down to address its business. An official conference song must be chosen, but songs sent in by hopeful contenders all sound like "We Are The World". Things liven up considerably, however, when the subject of lunch is broached. The board is particularly sensitive to the problems that may be encountered by visiting children unfamiliar with the English language and English food. Kitty Ann wonders how 800 people are going to eat at once. The talk is of buffets and roasts and cards you can fill in, like the ones you get in hospitals. Kitty Ann delivers the disheartening news that there will probably only be packed lunches.

"What kind of sandwiches do you have in Russia, Pavel?" she asks. He shrugs. "Fish." "Ugh," says Rebecca, "I hate fish." "Egg mayonnaise?" suggests Ben, speaking for the first time. "I like tuna salad sandwiches as long as they don't have mayonnaise," says Anna. Marmite attracts a unanimous verdict: "Really gross." The subject flows swiftly on to crisps and soft drinks before suddenly arriving at Frank Bruno. Some people wish that he could come to the conference. Frank Bruno, you see, is not gross. And he is not patronising