Defectors and spy satellites hold key to finding evidence of Iraq's nuclear weapons

Tony Blair said yesterday that there was "some evidence" that Iraq was close to acquiring a nuclear weapons capability, as he stepped up his rhetoric against Baghdad.

The Prime Minister gave every indication he had seen compelling intelligence which had convinced him of the need to act quickly against Saddam Hussein. How much of that intelligence information he intends to share with the British public, to persuade them war is justified, remains to be seen.

The evidence of President Saddam's nuclear and other weapons of mass destruction programmes will have come from three possible sources: Iraqi defectors, Western intelligence monitoring of foreign suppliers approached by Iraq, and information from the numerous spy satellites and other monitoring equipment trained on Iraq.

Satellite images in the public domain reveal that at least one Iraqi site under surveillance by the UN's nuclear team buildings have been erected. "We have questions, but we can't draw any conclusions unless we are in the country," said Jacques Baute, the Vienna-based leader of the international atomic energy agency (IAEA) action team.

This 15-member team, along with other UN weapons inspectors have been barred from Iraq since 1988. "Four years without inspections is a significant period for developing a nuclear weapon," Mr Baute added. "The more time passes, the greater the risk is."

In another possible sign of his nuclear ambitions, President Saddam has moved his nuclear experts to five locations in the country, a former UN weapons inspector said.

Making even a crude a nuclear bomb requires thousands of parts and tens of thousands of man-hours. Since Iraq was caught red-handed by the UN weapons inspectors in the past, there seems no reason to suppose President Saddam Hussein has abandoned his plan. In 1981, Israel preemptively knocked out Iraq's French-supplied Osiraq nuclear reactor on the well-grounded fear that it could be diverted for military use.

"There is no doubt that at some point the Iraqi regime were trying to develop nuclear weapon capability," Mr Blair said yesterday. "That's why the actual weapons inspectors went in there and shut down parts of their programme. I believe that there is evidence that [Iraq] will acquire nuclear weapons capability if they possibly can."

The problem for the Government in deciding to reveal its evidence is the danger that it will also uncover a "footprint" which could compromise its sources. A former UN official said: "The Government is in a bind. On the one hand they are asked: give us a rationale for invading and having young British people killed. But if you have any evidence you could be compromising sources." Similarly, Iraq defections known to US and British authorities have been kept confidential, while others are publicly known.

The limitations of showing the public views from satellite tracking are also well-known. "We could see that buildings are large, but not that there is something going on inside," the former weapons inspector said. He added that President Saddam was a past-master at tricking the UN monitors through a sophisticated concealment system. "The Iraqis had 10 years' practice in hiding all this stuff. They know what our sensors look for. One would expect them to be pretty good at dispersing all that."

And it is hardly likely that the British government will reveal which countries may be helping Iraq develop a nuclear weapon. German companies were among those involved in Iraq's early bomb attempt.

President Saddam began acquiring technology and equipment for nuclear weapons in 1987, using two organisations for procurement and development. The first, Al Qaqaa State Establishment, in Iskandariya near Baghdad, was thought to be in charge of developing the non-nuclear components for a nuclear weapon. The second, Nassr State Enterprise in Taji, also near Baghdad, was said to be responsible for Iraq's uranium enrichment effort. And agents in Europe were actively seeking weapon and uranium enrichment technology.

Under the sanctions regime declared after the 1990 Iraqi invasion of Kuwait, the IAEA came as close as it could to declaring Iraq's nuclear programme to have been dismantled before the UN inspectors left Iraq at the end of 1998. But it said finding "no indication" of any prohibited items or activities "was not the same as their 'non- existence".