"Senior Hussein regime officials informed the subcommittee that the allocation holders - in this case, Galloway - were ultimately responsible for the surcharge payment and, therefore, would have known of the illegal, under-the-table payment," he said.

Speaking to reporters before the hearing began, Galloway said the subcommittee's investigation was intended to take attention away from failed U.S. efforts in Iraq.

"It's the mother of all smokescreens," he said.

A report released last night by Democratic staff on a Senate investigations committee presents documentary evidence that the Bush administration was made aware of illegal oil sales and kickbacks paid to the Saddam Hussein regime but did nothing to stop them.

The scale of the shipments involved dwarfs those previously alleged by the Senate committee against UN staff and European politicians like the British MP, George Galloway, and the former French minister, Charles Pasqua.

In fact, the Senate report found that US oil purchases accounted for 52% of the kickbacks paid to the regime in return for sales of cheap oil - more than the rest of the world put together.

"The United States was not only aware of Iraqi oil sales which violated UN sanctions and provided the bulk of the illicit money Saddam Hussein obtained from circumventing UN sanctions," the report said. "On occasion, the United States actually facilitated the illicit oil sales. "

The leader of the anti-war Respect party insisted he would hold American leaders to account for what he believes are their crimes in Iraq....

He specifically criticized Norm Coleman, the subcommittee's Republican chairman, who claimed Mr Galloway had earned money from the OFF programme, although he conceded he had not seen the MP's bank account. Last night, the Scot said: "I'm going to insist he backs that statement up or withdraws it."

He said of the subcommittee that "by and large, they are vociferous supporters of Israel, vociferous supporters of the war and haters of the UN".