It was organised by the Stop the War Coalition (StWC), and included speakers from Iraq, the United States, and Italy.
Benn told the conference delegates that the anti-war movement which is calling for troops to be withdrawn from Iraq is the biggest he had seen in this lifetime.
Hassan Juma, president of the Iraqi Southern Oil Workers Union, condemned what he claimed were attempts by America to asset-strip Iraq through privatizing its services.
Sheikh Hussein al Zagani, a representative of Muqtada al-Sadr was due to speak at the conference, but was denied a visa by the UK government.
George Galloway, the Respect Party politician, ended the conference in which he urged people to build for a planned international demonstration on March 18, 2006.