“Rebel MP George Galloway's Respect Party has claimed that evidence he profited from Saddam Hussein's regime was forged.
Ahead of Mr Galloway's appearance in front of a committee of US senators in Washington, his party said the committee was relying on a counterfeit document created in Baghdad.
It said Mr Galloway's name had been pasted on to a list of people and companies alleged to have made money out of the Oil For Food programme.
His name appeared in a different typeface to other words on the same line, the print was lighter in colour and Respect suggested it had been stuck on and then the page re-photocopied.
His name also appeared at a slight angle and Respect said that would be impossible on the computerised document unless it had been artificially added.
Mr Galloway's party said there was a clear link between the list in the Senate Committee's report and one which appeared in a Baghdad newspaper in January last year.
Respect highlighted the claims of Sajad Ahmad Ali, who has previously claimed to have been involved in forging that list.
Mr Ali said: "We forged this list of names and titles of people who got money from the Ministry of Information, the palace and the Oil For Food.
"We worked for 10 days and then we steamed the papers a bit then dried them out so that they would look old. I beg anyone who reads his name in these papers to ask for the original version and check the date of the writing with carbon dating."