By Matthew Grant BBC News, Calcutta

Home to man-eating tigers, ravaged by cyclones and consisting mostly of mangrove swamps, the Sundarbans in the Bay of Bengal seems an unlikely setting for a rich man's playground.

The Sundarbans is the world's largest delta and mangrove forest

But the Indian billionaire Subrata Roy and his Sahara group have chosen the islands and waterways of the vast delta as the location for a $150m (�78m) project to build a network of luxury tourist resorts.

And before the company confronts the animals or the elements, it has another, perhaps greater problem to deal with: the tide of opposition from conservationists who believe the project will destroy the eco-system of the Unesco World Heritage Site.

Sahara hopes to take 300 tourists a day from Calcutta down the Houghly river to the Sundarbans biosphere reserve.

There, it plans to construct five-star lodgings on four coastal sites, with 75% of the accommodation on floating hotels.

High-speed catamarans would connect these resorts with purpose-built destinations, such as a crocodile breeding centre, eco-villages and handicraft markets - though plans for a golf course have been shelved.

The big draw for tourists who go to the Sundarbans is the Royal Bengal Tiger. But sightings are rare because of the dense mangrove forest.

Sahara's solution is to import retired circus tigers into the area and keep them in captivity.

Fragile eco-system

While the company insists it is taking every step to protect the environment, campaigners remain unconvinced.

Environmental campaigners fear for the mangrove eco-system

"The mangrove eco-system is the most fragile eco-system on earth," says Bonani Kakkar, who runs a prominent Calcutta group called Public.

"If you have a project of the size they're talking, the eco-system will collapse."

Another critic is Amitav Ghosh, whose latest novel The Hungry Tide is set in the Sundarbans.

While he is concerned about the damage he believes the project could do to the environment, he also says nature in the form of a cyclone could destroy it.

The word cyclone was even coined in the Sundarbans by the British in the 19th Century, when their attempt to build a port there was wrecked by a storm.

But Sahara seems undaunted - it has an evacuation plan and intends to build its resorts to withstand the worst.

Environmental impact

On the ecological issue, Sahara remains equally bullish.

It believes its project will not harm the eco-system and has prepared its own environmental impact assessment to try to prove it.

Four million people live in the area of the proposed development

"So far, we have not even touched a piece of soil in the Sundarbans," says Romi Datta, who heads the project for Sahara.

"We have spent four years investing money in only understanding and making sure as a responsible company, doing a joint venture with the government and the community, we don't go wrong anywhere."

The Sahara project is not actually in the World Heritage Site, he adds, but in the adjacent area where more than four million people live.

"I would say that our being there is actually going to enhance the biodiversity in the area and definitely improve the life of the people where we are going to be."

The director of Sundarbans biosphere reserve, AK Raha, also believes the Sahara project will prove positive.

"If nobody knows what the Sundarbans are, then we cannot make the whole world understand that we have to conserve the Sundarbans."

Test case

The Sundarbans tourism project is a public-private partnership with the government of West Bengal.

It has received all state-level clearances and is now waiting for the go-ahead from the government of India.

The Sahara group employs just under a million people and runs an airline and television channels.

To its critics, it is the Indian epitome of big business -and their desire to keep it out of the wildlife sanctuary is at least partly symbolic.

The film-maker and conservationist Richard Brock, who made The Living Planet series, recently visited the Sundarbans. For him, the project is a test case for the Indian government.

"If India bends its laws or changes things against the protection that already exists, I think India would then look as if it were letting down its reputation as a good conservation country," he says.