By Matthew Chapman in southeast Turkey

Serdar, who is 22, has trouble coming to terms with the fact that his family home will eventually be under 100 feet of water.

"I cannot believe this will happen," he says, slowly shaking his head. "We have lived here for hundreds of years."

Serdar is just one of an estimated 25,000 people whose homes are going to be flooded when the Ilisu Dam is built on the Tigris River in southeastern Turkey.

He lives in Hasankeyf, a breathtakingly beautiful town that hugs spectacular sandstone cliffs in the Tigris Valley.

He wants to know why Britain is considering backing the dam. "Nobody understands that here," he says, shaking his head.

Edinburgh-based Balfour Beatty are the lead contractor on the project.

They cannot go ahead without a guarantee from the British Government that it will stump up £200m if their own bills on the project are not paid.

British role

It is this demand for an export credit guarantee that has landed the government in the ethical quandary it now finds itself in.

Tony Blair has reportedly taken a personal interest in the scheme, arguing that keeping Turkey sweet as a partner in Nato and potential EU member outweighs the worries surrounding the project.

He has, however, apparently bowed to demands for conditions to be imposed for greater monitoring of the way the thousands of Kurds are moved out of their villages before the waters rise.

Local people find this last condition laughable, considering the Turkish Government's previous record on "evacuating" Kurdish villages.

The countryside of Kurdistan is littered with the burnt-out and bullet-riddled shells of villages which have been emptied at gunpoint by the army as part of their battle against the Kurdish guerrilla group, the PKK.

At least 19 of these villages are within the area to be flooded by the dam and in very few cases do those affected get any compensation.

"One day they came and told us they wanted to search our village," said Ahmed Boturai, a farmer whose family had lived in their village, just outside the dam-affected area, for generations.

"The next thing we saw the village on fire and we had to leave straight away - all my animals, my goats, they were all burnt. My children did not even have any shoes on their feet.

"Before we left all the men were made to lie on the ground and the soldiers poured kerosene on us and said, "if you come back we will burn you alive".

Armed conflict

Such tales of human rights abuses highlight the fact that an atmosphere for widespread public consultation on the dam simply does not exist in the region.

The bloody war between Kurdish guerrillas and the Turkish army, peppered with atrocities on both sides, was only brought to an end by a ceasefire five months ago.

Local people say the situation has not returned to anything approaching normality.

"We still live in constant fear," says Shenaz Turan, a human rights lawyer working in the regional capital Diyarbakir.

"All my friends have constant headaches and stomach pains because of the stress of always being picked up by the police."

Police pressure

When we visited the region to make a programme for Radio 5 Live we were constantly shadowed by the secret police.

Occasionally they would barge into interviews and demand to know what was being talked about. They would constantly stop us and ask to know who we were proposing to talk to next.

Some interviewees pulled out, saying they would lose their jobs if they were seen talking about the dam to Western journalists.

Standing on the cliff top over looking Hasankeyf, Serdar talks about how the dam has focused his own outlook on life in the last year.

Learning that construction work will begin later this year has altered his plans for university.

"I have decided to study the history of my region and my town," he says. "I wanted to learn the story of my home, to remember it, before the waters come and cover Hasankeyf."

The Blair Dam Project is made by All Out Productions for Radio 5 Live and is broadcast on Sunday 6 February at 1200 GMT.