An official tiger "census" puts the number of animals in the wild at around 3,700, but critics say that is more than double the true figure. Over 30 years since the threat to tigers was first recognised and Project Tiger launched by the then Prime Minister, Indira Gandhi, they claim tiger numbers are no higher now than then - around 1,800.

"We are currently at the same stage as we were in 1972, when Project Tiger began," said Neel Gogate, a local co-ordinator for WWF, formerly the World Wildlife Fund. "We are even behind that - because the human population pressures have gone up manyfold." Conservationist Valmik Thapar, who presented the BBC's Land of the Tiger series, has condemned Project Tiger for "poor management, corruption, lack of funding and outdated scientific methods".

The alarm was sounded last year, when the government was forced to admit that 122 tigers had been killed by poachers between 1999 and 2003. At the same time, it emerged that despite an official population of 28, no tiger had been seen in Sariska National Park in Rajasthan, one of the original reserves in Project Tiger, since October 2004. They are presumed to have fallen prey to poachers, lured by the fact that a single tiger carcass is worth $50,000 in the traditional Chinese medicine industry.

At Kanha National Park in the central Indian state of Madhya Pradesh, tourists riding elephants pay 600 rupees (£7.70) a time to view tigers. Queues of up to 30 four-wheel-drive vehicles can form to see one big cat.

The local field director of Project Tiger, K Nayak, insists that the official population of 136 tigers in Kanha is accurate, but critics say the counting method - the figure is arrived at through a combination of techniques, including pugmark analysis - amounts to little more than guesswork.

Mr Nayak was less certain about the issue of poaching. "I can't say it is completely under control, but I can say our tigers are more safe than previously," he said. But the prices paid for tiger parts must be an irresistible lure to some of the poverty-stricken villagers who have been moved out of the 1,000sq km core area of the national park, and he believed the answer to poaching was to give them different incentives.

"People will conserve the tiger if they get something out of the tiger," said Mr Nayak, who wants a tax imposed on the hoteliers who benefit from the tourists who visit Kanha. "Whatever they are earning, part of the money should go to the villagers." But Mr Gogate complained: "We really don't have the political will in favour of conservation."

The Sariska débâcle prompted a United Nations appeal last year to India, which is still home to the majority of tigers left in the wild, to take urgent steps to protect the big cats. The Prime Minister, Manmohan Singh, responded by setting up a task force, but conservationists say it is too little, too late.

"The tiger is on the verge of extinction in certain pockets," said Mr Gogate. "Look at what happened in Sariska - there are many more areas where I would say the situation is not grey - it is totally dark."