Benon Sevan, the United Nations official in charge of the oil-for-food programme in Iraq, intervened in person to steer lucrative contracts to an oil trader, Iraqi officials have told the UN's independent inquiry.

Their testimony, consistent with documents that have emerged since the fall of Saddam Hussein, adds to questions facing Mr Sevan as investigations into alleged corruption progress. The interim findings of the UN inquiry, led by Paul Volcker, are to be published on Thursday.