Calls by Swindon MP Julia Drown for a probe into America's sales of deadly toxins to Iraq have been squashed by the Government.

Foreign Office minister Baroness Symons said the export of bio materials had not broken international rules.

She said the US Government had acted in good faith when it authorised the sale of potentially lethal bio-toxins, later used by Saddam Hussein in illegal weapons projects. Baroness Symons said: "The United States did not believe that they would be used for anything other than legitimate research purposes and therefore did not knowingly export the materials to assist a biological weapons programme."

The comments mean attempts by MPs to have the US thoroughly investigated by the United Nations have failed. The South Swindon MP originally demanded action on grounds the US had apparently breached treaties designed to stop the spread of biochemical weapons.

The official sale of toxins to the Iraqi dictator between 1985 and 1988 was revealed in documents recently put before parliament.