Where tourists may not tread At risk: from Montmartre to the Galapagos, visitors are destroying what they have come to see... while bad management and corruption is endangering one of the world's great archaeological sites

TOURISM is posing such threats to wildlife, native populations and the environment that radical "no-go" areas may be introduced to protect them.

The travel industry is growing so quickly that tourists may be banned from sensitive areas such as the Egyptian pyramids; coral reefs in the Caribbean and the Indian Ocean; areas of the Himalayas; Costa Rican rain forests and the Galapagos Islands. The fear is that tourists, together with the infrastructure required to accommodate them, overwhelm the local people they visit. Demands on water supplies are heavy, rain forests are trampled away and increased car and coach use quickly pollutes areas.

The prospect of no-go areas will take centre stage at a seminar led by Professor David Bellamy to be held at the Royal Geographical Society next month. "I think in an ideal world there should be no-go areas," he said. "Certainly any areas which are natural or pristine or properly managed by indigenous peoples should be protected from tourism."

Another prospective speaker at the seminar, Martin Brackenbury, chairman of the Federation of Tour Operators, said some no-go zones were almost certain to be implemented before too long. Yellowstone and the Everglades national parks in the United States, which are on the World Heritage in Danger list issued by Unesco, are candidates that could, in the future, benefit from a ban on tourists.

But there are some closer to home. If the campaigners of the Montmartre district, in Paris, get their way, tour buses will be banned from the streets around Sacre Coeur. Our own national parks have also been under threat from overcrowding and traffic congestion for some time. Snowdonia National Park has just commissioned an audit on traffic use within its boundaries.

There are already several places where tourist numbers are controlled: visitors to the Andean ruins of Machu Picchu in Peru and to the Galapagos Islands in the Pacific are restricted. The Monteverde cloud forest reserve in Costa Rica only allows 100 visitors at a time and then only into one corner of it, while the rest is left undisturbed save for the odd botanist. In the Himalayan kingdom of Bhutan, border guards allow only a few thousand foreigners entry each year and charge them pounds 65 a day for the privilege of holding a permit.

However, many such schemes rely on tourists to obey regulations because eco-tourism laws are extremely expensive and difficult to police.

On a stretch of Costa Rica's Pacific coast, enforcement of environmental laws is the responsibility of just one policeman, and only when he can afford to put petrol in his motorbike to go on patrol. The conservation and tourism lobbies are divided over whether to welcome or fear the idea of taking control a step further and introducing no-go zones. Professor Bellamy has campaigned for many years for a single worldwide body to monitor and control tourism which would base its decisions on green audits of existing and potential sites. "At the moment we do not have a central, international tourism body laying down the rules for tour operators and tourists to follow."

According to Martin Brackenbury, some no-go zones could benefit not just local residents and the environment but also tourist companies.

"No-go areas would not necessarily be obstacles to tourism," he said. "Sometimes there is such growth in tourism that it starts to affect the industry adversely. We have said over the past three or four years that it was a mistake for Majorca to continue building hotels and it agreed. They have not built any new beds in Majorca during that time. In fact they have pulled down a lot of hotels."

Judging by United Nations predictions, this is not before time. Visitors to the Mediterranean could reach 760 million by 2025 adding to a population of 150 million and putting great strain on the local environment by increasing the amount of sewage discharged into the sea and endangering its wildlife.

However, there are arguments against no-go zones. Robin Hanbury-Tenison, an explorer and the president of the tribal rights group, Survival International, said that while they might provide beneficial isolation for fragile peoples of the world and protect them from exploitation, he was sceptical about such measures.

"I don't like the ideas of no-go areas in the same way that I don't like censorship. It reminds me of apartheid," he said.

Simon Beeching, managing director of the travel group Wexas, who is also speaking at the RGS seminar, said that rather than travel bans there should be "a balance struck between the industry and the environment". It is possible to build hotels that can enhance the environment and improve bio-diversity, he feels.

"It is a case of accepting the hard-nosed commercial reality of the travel industry," he said. "But the industry in turn must learn not to kill the goose that lays the golden egg. It must realise the importance of protecting sites which attract tourists so they will keep coming back."

So, if you find yourself booking a holiday in the next few years and hear the age-old travellers' joke "I went to New Zealand last year and it was closed", it may be for real.