From the UK Telegraph:
The French secret service is believed to have refused to allow MI6 to give the Americans “credible” intelligence showing that Iraq was trying to buy uranium ore from Niger, US intelligence sources said yesterday.
MI6 had more than one “different and credible” piece of intelligence to show that Iraq was attempting to buy the ore, known as yellowcake, British officials insisted. But it was given to them by at least one and possibly two intelligence services and, under the rules governing cooperation, it could not be shared with anyone else without the originator’s permission….
British officials admitted that the country was Niger but insisted that the intelligence behind it was genuine and had nothing to do with the fake documents. It was convincing and they were sticking with it, the officials said.
They dismissed a report from a former US diplomat who was sent to Niger to investigate the claims and rejected them. “He seems to have asked a few people if it was true and when they said ‘no’ he accepted it all,” one official said. “We see no reason at all to change our assessment.”
The fake documents were not behind that assessment and were not seen by MI6 until after they were denounced by the IAEA. If MI6 had seen them earlier, it would have immediately advised the Americans that they were fakes.