Source:
The Guardian· Time lag as agencies checked out conversations
· Ahmadinejad basks in 'great victory' of report
The US intelligence U-turn on Iran was partly based on telephone conversations in Iran intercepted by the British intelligence listening station GCHQ, according to a source in Washington speaking on a basis of anonymity.
In an updated assessment of Iran published on Monday, the US intelligence agencies concluded that the country had ceased work on a nuclear weapons programme four years ago, in contrast with its assessment in 2005 that the country was pushing ahead with its weapons programme.
George Bush said on Tuesday that the decision to change the assessment was based on "a great discovery". Diplomatic and official sources in the US said this was mainly based on human intelligence, almost certainly a major defector, but that intercepts were also a factor.
According to the source, there was a lengthy time-lag between the conversations being intercepted by GCHQ and the US intelligence agencies checking out whether they were genuine or whether those involved knew they were being listened to and put out false information.
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