EXPERTS and archaeologists have welcomed the inclusion of Peru’s Machu Picchu among the modern-day wonders of the world, but fear it could spell the destruction of the ancient Inca citadel.

“Look, we do not want to dampen the euphoria over the honour granted to Machu Picchu, but with it comes immense responsibility,” said Alberto Delgado of the NGO Instituto Machu Picchu, dedicated to the monument’s preservation. “The site is already being badly damaged by tourists and could reach a point of no return should strict measures not be implemented right now.”

Machu Picchu - which sits 8,000ft above sea level on a shelf jutting out of the Andes - was one of the few Inca centres that escaped the destruction of the Spanish Conquistadors. More than 500 years later it seems the new wave of invaders, tourists clad in Timberland boots and North Face jackets and armed only with hard currency, may succeed where the conquistadores failed.

UNESCO, which recognises Machu Picchu as a World Heritage Site has already threatened to put the citadel on its ‘at risk’ list and is seeking a series of measures introduced to halt damage.

It wants to concentrate on halting the erosion caused by hundreds of thousands of tourists clambering over the 600-year-old ruins and the damage to the ecosystem over which Machu Picchu presides. It is surrounded by a cloud forest, where the Andean mountains drop into the Amazonian jungle, supporting rare species of flora and fauna, among them some of the most spectacular orchids in the world.

The greatest damage in the short term comes from the town of Aguas Calientes, which sits at the foot of Machu Picchu, a new settlement that has sprung up to take advantage of the tourists attracted to the site. There has been uncontrolled development and building as hotels, clubs and restaurants spring up, polluting the region and upsetting the sensitive balance of the ecosystem. Archaeologist and former head of Peru’s National Institute of Culture (INC), Luis Lumbreras, believes the site is under a very real threat, not just from erosion, but from the buses winding up the mountain, carrying the 2,500 tourists allowed to visit the site every day.

“The vibration of the buses is increasing the risk of parts of the citadel shelf, which is built on granite, falling away,” said Mr Lumbreras. “Fault lines have already been traced.”

Machu Picchu is big business, generating some £30 million every year, and indirectly attracting much of Peru’s £400 million tourist industry. One of the winners from the new recognition of the site will be the British company Orient Express Hotels Ltd, which holds a monopoly over the rail service that links the city of Cusco with the Inca citadel. In a concession granted by disgraced president Alberto Fujimori, currently in prison in Chile, Orient Express Hotels Ltd has 50 per cent control of the railway and the only hotel by the site, the Machu Picchu Sanctuary Lodge.

The INC knows something has to be done and is scrambling to find answers so as to take advantage of the inevitable increase in visitors without permanently damaging the site.

“We are looking for strategies as to how we can handle the inevitable tourist avalanche that will result from the site being declared a wonder of the world,” said Ana María Hoyle of INC.

One of the options being studied is changing the time a ticket is valid. At the moment visitors can buy an all-day ticket, leave the site to eat then return for the afternoon. That may become a thing of the past as tourists are given a strict timetable and forced to view the citadel in supervised groups to prevent climbing over vulnerable parts of the site.

The ‘New Seven Wonders of the World’ campaign was begun in 1999 by a Swiss adventurer, Bernard Weber, with almost 200 nominations coming in from around the globe.

Mr Weber “felt it was time for something new to bring the world together” and to “symbolise a common pride in the global cultural heritage”, said Tia Viering, a spokeswoman.

Mr Weber’s Switzerland-based New7Wonders foundation aims to promote cultural diversity by supporting, preserving and restoring monuments. It relies on private donations and revenue from selling broadcasting rights.

The original list of seven wonders was compiled in the second century BC by Antipater of Sidon. It featured the Ishtar Gate, one of the entrances to the ancient Mesopotamian city of Babylon.

Another list of seven wonders appeared in around the sixth century AD, replacing the gate with the lighthouse of Alexandria. But by the time it appeared, many of the sites had gone - and the existence of the Hanging Gardens of Babylon has never been proven.