Yesterday the Ministry of Defence said it had no information about the project but admitted it was 'slap-bang in the middle of the area the RAF are looking at'. The RAF at Dhahran, Saudi Arabia, said the results of the first Tornado reconnaissance flights over the exclusion zone in southern Iraq had not been released, and was unable to say whether they had flown over the engineering works.
But the UN human rights investigator, Max van der Stoel, and other observers have warned that the canal will drain the area where the Marsh Arabs are under attack by 75,000 troops, breaching their natural defences and possibly destroying their environment and way of life for ever.
Last week 735 pieces of plant and 4,500 workers worked round the clock to cut the last seven-mile sector of the 350-mile canal from Baghdad to the Gulf. The last section is near Dalmaj, 135 miles south-east of Baghdad. Three thousand heavy machines were working along the entire length of the canal.
Water supplies are of great strategic significance in the Middle East: one reason why Israel is so sensitive about the Golan Heights is that they shield the river Jordan. Anyone controlling the Jordan's entry into Israel could parch it into submission.
The Iraqis have a tradition of giant geo-strategic projects. At the beginning of the 1980-1988 Iran-Iraq war, aerial photographs revealed a giant trench, one kilometre wide and 30km long, east of Basra, which is now part of the map of the area. At the southern end it expanded into a 10km- wide lake.
Some said it was part of an ambitious grand-strategic project to take water from Khuzestan: others that it was a giant moat to defend Basra from Iranian attack.
The third river could also serve several purposes. It is extremely ambitious, and by completing it in such a determined fashion Iraq is showing its defiance of international sanctions, its engineering prowess and its ability to recover quickly from defeat in the Gulf war.
Water communications have always been vital in this part of the world and strategists like canals. Unlike roads and railways they cannot be cut by bombs or explosives and supplies moving along them are easy to defend.
The Iraqis also feel vulnerable because the Turks, who control the headwaters of the Euphrates, have instituted the Gap project, reducing the level of water in the river. The canal, between the Tigris and Euphrates, can also be used to transfer water from the former to the latter.
Lastly, the Third River will drain the marshes, although there are other schemes to drain the marshes as well, and it is not clear whether this is a primary or subsidiary aim of the Leader's River.
The marshes are not only the home of the Marsh Arabs, but since the early 1980s have been a haven for deserters. Because they straddle the Iran-Iraq border, they are also an easy route for infiltration from Iran. Draining them would therefore solve several problems.
But last week the Iraqi deputy agriculture minister, Abdul Sattar Hussein, said: 'There is no connection whatsoever between this project and the question of the marshes in southern Iraq.'
Intelligence sources have also played down suggestions that the project's primary aim is to drain the marshes.
There have also been reports of causeways built into the marshes to enable the Iraqis to get tanks and artillery closer to targets. One source said that if you dig a canal, you inevitably throw up banks of earth, which look like causeways.