Thanks to drought and increasing Israeli security restrictions on where they can wander, their nomadic lifestyle, which predates the birth of Christ, is likely to die out within a generation.

Lack of rainfall over the past three years, thought by some to be due to climate change, is gradually rendering many already sparse grazing lands unusable for their flocks of goats and sheep. At the same time, the steady growth of Jewish towns and settlements in the Israeli Negev desert and the West Bank has left the 280,000 Bedouin of the region with ever fewer options for moving to better pastures, their traditional way of surviving when times are hard.

"This is the worst dry year for the Bedouin," declared Suleiman al-Hathalin, standing among the ramshackle collection of tin shacks and tents that mark his family's land at Khirbet Umm al-Khair, an unrecognised Bedouin village in the West Bank hills south of Hebron. "My father and my uncle had the chance to live a true Bedouin life. But I am being deprived of this and now so are my children. The life of the Bedouin, the freedom of movement – it's finished."

At present, most Bedouin tribes are still stubbornly clinging on, spending what little money they have on artificial feed for their animals rather than succumbing to government pressure to resettle into towns with running water and electricity.

However, the International Committee of the Red Cross warns that a way of life that has survived wars, occupations, famines and calamities stretching back to Biblical times may be finally coming to end.

"Their lifestyle is under threat," said Helge Kvam, a spokesman for the committee's mission in Jerusalem. "They need to get better access to water and grazing sources. And at the end of the day, that requires a political solution."

With their camels, flowing robes and warm hospitality, the Bedouin have long been the symbol of life in the harsh desert, brought to fame as the desert warriors who guided Lawrence of Arabia during his First World War campaign against the Ottomans in the Middle East. Many can still pull out land deeds dating to the Ottoman Empire or at least the more recent British mandate, establishing their traditional territory, and historians say evidence of their existence here stretches back beyond the 11th century BC.

But modernisation is slowly overcoming their traditions, while their land claims have been eroded by years of war and development. Now, with the Bedouin forced to the margins of their historic territories and unable to roam freely, the continuing drought and rising food and fuel prices come as a crippling final blow.

Mr al-Hathalin's family has lived a traditional nomadic life for generations, housed in tents and rough shacks and moving from field to field with their sheep and goats as the seasons change. As recently as the 1950s and 1960s, they were comparatively well-off, with large herds of both sheep and camels.

Today, however, Mr al-Hathalin and about 80 members of his extended family support themselves with just 100 hardy goats and supplement their diet with United Nations food rations. Their home is a shanty village of tin shacks and tents, jammed against a fence separating them from a Jewish settlement nearby.

Two of their dwellings, one of concrete and another of tin, have been demolished by the Israeli army, which is trying to relocate them to another piece of land a few miles away.

Hemmed in by borders and checkpoints, they cannot move their goats to find better grazing, and the whole village relies on a trickling water supply from a single pipe. As a result, their animals are sickly and hungry, and their children go unbathed for weeks.

Bedouin in Israel do receive some support from the government, though state efforts to resettle them into eight official villages in the desert have led to high unemployment and social decay. A state committee is examining how to manage 45 other, unrecognised villages, which are under formal demolition orders and without running water or electricity. "Right now we are trying to do our best to help with many projects. We are investing a lot of money into this area, into schools and health care," said Dror Soroka, a programme manager with Israel's Ministry of Development in the Galilee and Negev, who defended the policy of resettlement.

"I truly believe the young people see what is happening in the world and they want to achieve a little more – they want to live in the world, they want a good education, they want better jobs," he said.

The Bedouin of the predominantly Palestinian West Bank, however, enjoy none of those efforts. Harassed by Jewish settlers from a radical settlement nearby, they are up against Israeli army orders to relocate them and demolish their decrepit homes. But as West Bank residents, they fall under the jurisdiction of the Palestinian Authority, which offers no similar programmes.

Mr al-Hathalin's son, Eid, 23, wonders if he can continue in his father's footsteps. He is a high-school graduate who speaks the English he learned at school with a shy smile, but his family cannot afford any further education for him. But, although he carries a mobile phone and yearns for the money to buy a truck, he says he will not give up on his family's traditions. "Of course it's getting harder and harder. But we want to have hope," he said.