So, does Saddam have hidden weapons of mass destruction? Blair and Bush insist Iraq has biological and chemical arms, and poses a genuine threat to the civilised world, but there is little concrete evidence which would stand up in court, reveals Ian Bruc

Instead of sticking to the usual routine of tea and meaningless pleasantries with the facility's director in advance of a fruitless scan of documents and equipment, Dr Seaman raced up the staircase to the building's administrative office on second floor.

There she found two officials from Saddam's sinister special security directorate stuffing documents into briefcases. Both fled, leaving a paper-trail in their wake, as the slightly-built biologist gave chase down a corridor. Cornering them in a lab, she managed to wrestle the briefcases from their grasp as three others of her team arrived to give support. The papers liberated in the tussle contained details of a project to develop clostridium perfringens - gas gangrene - as a useable battlefield weapon.

In seven years of increasingly frustrating monitoring operations, such victories were few and far between.

On another occasion, fear of what the inspectors might discover prompted one Iraqi ''minder'' to seize the controls of a UN helicopter when it flew too close to a site suspected of containing contraband missile equipment.

The petrified United Nations Special Commission (Unscom) scientists were subjected abruptly to an aerobatic experience most would gladly have forgone as the aircraft begin to pitch and yaw around the sky. The pilot finally delivered a right hook to the Iraqi official and managed to execute an emergency landing just before his helicopter went into a terminal spin. When Saddam finally tired of cat-and-mouse games with UN scientists he had branded ''spies'' and whom he accused of interfering with Iraqi sovereignty and dignity, they were expelled in December, 1998. It was a move which brought on the aerial wrath of the US and the UK in Operation Desert Fox. But it freed Baghdad of intrusion into secret projects.

Unscom, despite Iraq's obstruction, denial, and outright lies, had been remarkably successful to the extent that any such oversight of clandestine activity can ever be judged to be a success.

As one former inspector told The Herald: ''I could create a basic biowar project with a few handfuls of backyard dirt and a high school chemistry set. The details are available on the internet. Weaponising the end product is a bit more complicated, but not a problem for a country the size of Iraq and with Saddam's resources in equipment.''

By the time the inspectors left the military hotel they had been allocated in Baghdad, a building where the showers dispensed steam but no water, and where the telephones rang at intervals through the night to disrupt their sleep patterns, they had halted Saddam's nuclear programme in its tracks and put a temporary kink in his quest for long-range missiles.

They had destroyed or supervised the destruction of 48 Scud missiles, 30 warheads for chemical or biological payloads, and 480,000 tonnes of lethal nerve agents such as sarin and tabun.

Centrifuges and dual-use equipment which could either help in the manufacture of pharmaceuticals or provide the basis for biological brews capable of wiping out the population of entire cities had also been destroyed.

A crash programme to develop a crude but useable nuclear warhead involving 3000 Western-trained Iraqi physicists had been only months from completion when the Gulf war intervened. Unscom diligence forced Saddam to transfer many of his scientists to other, less expensive projects.

But Unscom's painstaking tracking of Iraqi purchases worldwide showed alarming discrepancies between what could be accounted for in chemical

or biological stocks found and neutralised, and amounts known to have been produced.

Up to 4000 tonnes of precursor chemicals for the manufacture of nerve gases were never found. A further 17 tonnes of growth medium for anthrax and botulism remains unaccounted for.

Botulinum toxin is about three million times more lethal than sarin nerve gas, and a microscopic droplet of sarin is enough to kill a human being. In ideal weather conditions, a Scud warhead filled with botulinum could contaminate an area of 3700 square kilometers. It takes a few hours to incapacitate its victims and 12 hours to kill them.

Anthrax, viewed as ''the poor man's nuclear weapon'', takes four to five days to take effect. Then it will kill eight out of every 10 people infected. It is also persistent. Gruinard Island off the Scottish coast was used to test it during the Second World War. It was declared safe again only 50 years later and is still not recommended as a tourist destination.

Iraq also has unknown quantities of VX nerve agent, perhaps the deadliest of all military gases. Unscom technicians found traces of the substance on Scud warhead fragments. Baghdad had strenuously denied possessing the agent, but suddenly remembered that it had made ''small quantities'' after a highly-placed defector provided the UN with chapter and verse on forbidden research in 1995.

For a dictator such as Saddam, biological agents are the perfect weapons. They are both cheap to manufacture - basically growing themselves after a kick-start in a lab - and many can be made as by-products of legitimate pharmaceutical processes.

The yeast from a brewery is a perfect growth medium. The raw mash used to convert castor beans into harmless family medicine contains ricin. In concentrated form, it becomes a highly toxic biowar weapon with an 80% kill rate.

There have been intelligence reports that Iraq is using mobile labs built

into the back of specially-adapted

juggernaut trucks to keep its ongoing biological programmes both mobile and undetectable.

The BND, Germany's secret service, claimed last year that Saddam's engineers are working flat out to develop a 2000-mile range missile using parts smuggled in by front companies in India and Europe.

The Germans also say such a missile could be operational in as little as four years and tipped with a nuclear warhead a year after that. A cadre of 300 leading Iraqi scientists has been engaged in computer simulation experiments to keep the atomic dream alive. The BND contends that if the embargo on fissile material were lifted, a bomb could be available within 12 months.

Both Britain and the US have postponed briefings in recent weeks at which Tony Blair and George W Bush were to have unveiled dossiers supplying incontrovertible evidence of Saddam's continuing crusade to acquire nuclear, chemical, and biological weaponry.

The information to be given was designed to allay the misgivings of those on both sides of the Atlantic that Saddam was being set up for a military hit under the doubtful criterion of the war against terror.

More importantly for the UK, the ''evidence'' was supposed to silence the growing protest from left-wing Labour back benchers over Blair's gung-ho support of a new war against Iraq on America's say-so. Many have the uneasy feeling that George Bush Junior is merely trying to take care of unfinished business in the Gulf on his father's behalf.

Most of the information about what is going on inside Iraq in the absence of Unscom comes from defectors. Much of that is coloured by the anticipated pay-offs for juicy tidbits. One Iraqi physicist claimed that Saddam had already carried out an underground nuclear test, an assertion not backed by any seismographic evidence.

The highest-ranking defector so far was Hussein Kamil Hassan, Saddam's son-in-law and the man in charge of all major military-industrial projects. He fled to Jordan with a collection of incriminating documents and $25m in stolen state funds.

He was interviewed by Unscom, the CIA, and agents from the US Defence Intelligence Agency. The most important revelation was that Saddam had produced VX nerve gas and managed to weaponise it to the point of putting it in warheads. Most of the other data he volunteered was either already known or of doubtful value.

Adozen other defectors from various levels of Iraq's tightly-controlled central administration have added surprisingly little to Unscom's files. Most say research and production facilities for mass destruction weapons are concealed in underground complexes deep beneath Saddam's many palaces.

The bulk of alternative intelligence has been gleaned from U2 spy plane overflights, interception of communications, and satellite surveillance. Special attention has been focused on detecting signs of heavy traffic to and from facilities, power usage, and levels of security, all indicators, though hardly evidence, of secret projects.

High-flying manned aircraft equipped with ''sniffer'' devices

capable of picking up minute traces of chemical or biological residue have also been used.

The problem for the British and US governments in producing ''evidence'' that a sceptical public and an even more sceptical political opposition will accept as the basis for hostilities is that much of it is either circumstantial or anecdotal. Ironically, the hardest intelligence must remain classified in case it compromises sources or alerts Iraq to scrutiny of which it has been unaware.

There are clearly few ''humint'' sources, the old-fashioned agents using eyeball technology to spy on the regime, although Saudi Arabia's espionage network and Israel's Mossad are believed to have spies on the ground. An Iraq armed with long-range, mass destruction biological or nuclear firepower is a threat to both.

Seven years of close scrutiny by Unscom's teams taught Saddam many tricks of concealment. The fact that the inspectors were blissfully unaware of the VX project until it was exposed by a defector proves how effective his security apparatus became.

Israeli sources say that his engineers have even constructed modern laboratories with overpressure chambers designed to contain germs inside otherwise dilapidated structures - literally houses within houses - to conceal their true purpose.

The bottom line is that everyone knows Saddam has stocks of biological and chemical armaments, and is probably augmenting those stocks by the week, but there is little concrete evidence which would stand up in court.

Even the twin-track approach of trying to pin support for terrorists on the Iraqi dictator has fizzled out. George Tenet, the CIA director, told a US senate committee recently that there was ''no proof that Iraq has engaged in terrorist operations against the United States in nearly a decade''.

Richard Butler, the bluff Australian diplomat who headed the Unscom effort in Iraq in 1998, said: ''Saddam has a whole cocktail cabinet of chemical and biowar nasties. Whether he has the means to use them is another question.''