No party has "secret sources of Intelligence" on Iran ......

NEWSWEEK/ here
"The U.S. position is contained in a controversial National Intelligence Estimate, produced in 2007. This document said that U.S. agencies "judge with high confidence that in fall 2003, Tehran halted its nuclear weapons program" and that "the halt lasted at least several years." The 2007 NIE also said that American agencies assessed "with moderate confidence Tehran had not restarted its nuclear weapons program as of mid-2007, but we do not know whether it currently intends to develop nuclear weapons."

... U.S. intelligence agencies today still stand by the 2007 assessment. So the American position would appear to be at odds with the U.K.'s expression of "skepticism" that Iran stopped work on nuclear weapons in 2003......

Several U.S. and European officials said they were confident that the allied agencies—including CIA, MI-6, Germany's BND and Israel's Mossad—were working from the same raw information. In other words, neither the United States nor any of the allies have secret, unilateral sources of intelligence which would lead them to different conclusions about Iran's bomb efforts, the officials maintain.

Two of the European officials suggested that the American assessment is very cautious because U.S. intelligence analysts still feel burned by their mistakes in the run-up to the Iraq War, when faulty intelligence was used by Bush administration officials to justify military action.....

European and U.S. officials also note that in the run-up to the Iraq War, some analysts inside U.S. agencies felt they were under political pressure to produce alarming assessments of the threat Saddam posed to the world. By contrast, the American and European officials say, there are no signs that Obama administration policymakers are putting political pressure on U.S. intelligence agencies regarding their conclusions about Iran's nuclear program.

So why are American and European analysts coming to different conclusions? One possible reason is that the Europeans regard evidence of Iranian progress on uranium enrichment—including the discovery that Iran has been constructing a secret underground enrichment facility on a military base near the holy city of Qom—as evidence that Iran continues actively to develop nuclear weapons. By contrast, the official U.S. analysis—while acknowledging that Iran is moving ahead with uranium enrichment, the most difficult part of building a bomb—does not regard this as part of the research and development of an actual bomb and the mechanism to explode the uranium......

Israel, according to U.S. and European officials, takes the most alarmist view of Iranian nuclear progress. Its analysts argue that even if Iran is not actively building a bomb, once it assembles the capability to do so, Israel's existence could be threatened. The officials say Israeli analysts believe Iran is dangerously close to acquiring this capability...."