Why didn't Tony Blair and George Bush mention Saddam Hussein's most terrible war crime? Why, in all their "dossiers", did they not refer to the 5,000 young men and women who were held at detention centres when their families – of Iranian origin – were hurled over the border to Iran just before President Saddam invaded Iran in 1980?

Could it be because these 5,000 young men and women were used for experiments in gas and biological warfare agents whose ingredients were originally supplied by the United States?

Just months before his September 1980 invasion of Iran – in which tens of thousands of Iranian soldiers died an appalling death by gas burns and blisters – Saddam's Interior Ministry issued directive No 2884, dated 10 April 1980, stating that "all youths aged between 18 and 28 are exempt from deportation and must be held at detention centres until further notice".

Most, though not all, of the young men and women affected by this order were Kurds. None of their families ever saw their loved ones again, but they have since been told that the detainees were killed during experiments in gas and chemical warfare centres in Iraq.

Among the most terrible war crimes committed during the Second World War were the Japanese experiments with chemicals and gas on prisoners at Harbin, in occupied China. US officials ensured that the principal culprits got away in return for the results of their experiments. The Nazis ran medical tests on Jews in extermination camps in Europe, some of whose "doctors" also escaped punishment.

As always in Iraq – and elsewhere in the world – there is no proof. Kurdish families to whom The Independent has spoken pleaded with us not to reveal their names, in the pathetic hope that their sons and husbands and daughters might still be alive. They include the father of a young man who was taken from his family home in Baghdad, and the father of a man who was allegedly sent to the front line during the Iran-Iraq war and who died as a "martyr" months after his death during a medical experiment.

With the encouragement of President Bush Snr, the US Department of Agriculture sent Iraq samples of chemicals that could be used to protect crops and other agricultural produce, with pesticides that were later developed for chemical warfare, despite repeated warnings from American officials that the cultures could be of use against human beings.

Just before the September 1980 invasion of Iran, the detentions began. At least 5,000 "Kurdish youths", according to one Iraqi refugee interviewed by The Independent, "vanished into thin air".

According to one Iraqi dissident, whose refusal to ally himself to the Iraqi opposition is much to his credit in the picture that is emerging, a large if unknown number of young detainees may have perished as a result of being used as guinea pigs for Saddam Hussein's research programmes at various chemical, biological and nuclear warfare laboratories. According to the same source, Iraqi scientists who have since defected to the West have given hints of the biological warfare testing programme but have refused, for obvious reasons, to incriminate themselves. Iraqi-Iranian Kurdish families who have received appalling information about the fate of their relatives have refused to keep quiet. One father of five missing boys gained an audience with an Iraqi vice-president who allegedly told him that one of his sons had been imprisoned for opposing President Saddam but had then had an "awakened conscience". The boy had decided to fight in the war against Iran and had died in combat, his body being "lost".

According to an Iraqi Kurdish refugee in Lebanon who regards the official Washington- supported Iraqi opposition as fifth columnists, Western intelligence has long known the fate of the 5,000 or more "detainees". "It is now clear," he says, "that during the war with Iran many of the young detainees were taken to secret laboratories in different locations in Iraq and were exposed to intense doses of chemical and biological substances in a myriad of conditions and situations. With every military setback at the front causing panic in Baghdad, these experiments had to be speeded up – which meant more detainees were needed to be sent to the laboratories, which had to test VX nerve gas, mustard gas, sarin, tabun, aflatoxin, gas gangrene and anthrax." In the early stages of the Iran-Iraq war, Iranian troops stormed across the Baghdad-Basra highway and almost cut Iraq in half – to the great concern of Washington.

But not one of the many accusations levelled against Saddam Hussein's regime by London and Washington mentions the missing 5,000 young people "detained" by Iraq just before the outbreak of the Iran-Iraq war.

This could, of course, reflect the West's embarrassment at its support for Iraq during that war. Or it could be an attempt to avoid any inquiry into how President Saddam obtained the means to wage chemical warfare against his opponents.

SEE HOW Rumsfeld was Saddam Partner in Chemical Crimes:  http://www.commondreams.org/views02/0802-01.htm