The TUC served notice on the Prime Minister yesterday that the union movement would not tolerate an Anglo-American attack on Iraq.
A declaration passed overwhelming by delegates urged that military action should only be launched with the explicit endorsement of the United Nations Security Council.
A more hardline left-wing amendment, which sought to rule out an offensive against Saddam Hussein completely, was defeated after a card vote.
The statement, drawn up by the TUC's ruling general council and passed on the eve of the Prime Minister's address to the TUC congress in Blackpool, called for a deadline to be issued for Iraq to accept inspection of its weapons programmes.
An attack on Iraq should only be sanctioned on the basis of evidence that President Saddam was developing weapons of mass destruction and that his regime constituted a threat to world peace.
Tony Blair's aides said the Prime Minister was "relaxed'' about the statement, but it is known that No 10 had attempted to water it down.
Delegates overwhelmingly endorsed a general council statement that urged the creation of a Palestinian state alongside Israel. The statement called for an immediate end to Israeli occupation of Palestinian territories.
Arguing against an attempt to ban military action against President Saddam in perpetuity, Roger Lyons, joint general secretary of the Amicus trade union, said the regime had been guilty of torture, persecution and murder. "His abuse of humanitarian relief is well documented. Two and a half billion dollars of humanitarian aid for food remains unspent. The Kuwait authorities recently seized a ship-load of baby milk and bottles, being illegally re-exported from Iraq for profit. And hundreds of thousands of tons of rice have also been sold for profit."
Over the life of the aid programme, nearly half of the medical supplies had been kept in warehouses rather than being given to the people who needed them, Mr Lyons said.
He added that during the Iran-Iraq war, chemical weapons were used against Iranians, causing 20,000 casualties. The Marsh Arab community in southern Iraq was also "mercilessly attacked'', the Amicus leader said.
Mr Lyons said that after the invasion of Kuwait, Amnesty International uncovered and identified 38 methods of torture used on prisoners, including eyes gouged out, burning and electrocution. "And no one can forget the babies thrown out of the incubators in Kuwait, so the equipment could be taken back to Iraq."
He said President Saddam pioneered the concept of the "human shield", using terrified women and children in an attempt to hold off military action in Kuwait. Acting through the United Nations, the international community should prevent the Iraqi leader unleashing terror abroad. And trade unionists should back UN action to help those trapped within his outlaw state.
Billy Hayes, the left-wing general secretary of the Communication Workers Union, said Mr Blair should "give peace a chance", quoting a John Lennon song.
Arguing in favour of a complete ban on military intervention in Iraq, he said that such a policy would have the full support of the British public.
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