Iranian President Mahmoud Ahmadinejad has written a letter to George W. Bush proposing new ways of resolving their differences.It is the first letter from an Iranian head of state to a US president since 1979. The contents of the letter are as yet unknown but Iran’s top nuclear negotiator says there has been no softening of position on the enrichment of uranium. In Washington, US intelligence chief John Negroponte says the letter may have been timed to influence a UN Security Council debate on how to tackle Iran’s nuclear programme. “Certainly one of the hypotheses you’d have to examine is whether and in what way the timing of the dispatch of that letter is connected with trying in some manner to influence the debate,” he said. Informal discussions have already taken place at UN headquarters between Security Council members, with no breakthrough towards a common stance.