Opponents of UN sanctions against Baghdad allege that Israel has been permitted to defy resolutions for the past 30 years ordering it to quit the West Bank and Gaza, while Iraq's non-compliance has been punished by repeated bombings and a rigorously enforced trade embargo.

President Bush's speech to the UN general assembly in New York today recognizes mounting international pressure for a fresh resolution against Iraq before any military action is taken.

His critics are unlikely to be persuaded. "The US has consistently employed a double standard when it comes to UN resolutions and international law," maintains Voice in the Wilderness, the campaign to end economic sanctions against Iraq. "For decades the US has vetoed UN resolutions condemning Israel's occupation of Arab territories."

Professor Malcolm Chalmers, who teaches international studies in the department of peace studies at Bradford University, agrees that UN resolutions reflect political relationships between permanent members of the security council and their allies.

"The way the security council works from the beginning is governed by its composition," he says. "In the case of Iraq the driving force is not what the United Nations said but what the major powers and the United States see as their priorities.

"There are other countries which have not complied with international treaties. Israel has been supported by America. It's a reflection of the modern world in which the US is the only power with the military might to enforce resolutions."

Sir Adam Roberts, professor of international relations at Oxford University, believes there is a fundamental difference between the UN's forthright condemnation of Iraq and its disapproval of Israel. "The comparison that is frequently made between Iraq's response to the resolutions relating to disarmament and Israel's responses to the resolutions about occupation of the West Bank and Gaza is a facile comparison," he says.

"The resolutions of the security council 242 and 338 call on all the parties to negotiate a peace settlement and it's perfectly possible to argue that serious attempts have been made ... and that responsibility for failure is not entirely Israel's fault.

"By contrast the resolutions on Iraq from 91 ... call unequivocally on Iraq to take certain actions and accept certain conditions as a quid pro quo for the ceasefire, and Iraq has been said quite clearly by the security council in 1998 to be in 'flagrant violation' of various resolutions. That was unanimously passed by the security council in resolution 1205 of 98. Iraq is the only state the security council itself has said is in flagrant violation of its resolutions."