Osama wrote to Al Qaeda deputy Atiyah Abd al-Rahman: ‘The reason for concentrating on them is that Obama is the head of infidelity and killing him automatically will make [Vice President] Biden take over the presidency, Biden is totally unprepared for that post, which will lead the U.S. into a crisis.

‘As for Petraeus, he is the man of the hour … and killing him would alter the war’s path’ in Afghanistan.’

Osama’s ambition was to have Ilyas Kasmiri, described by U.S. officials as Al Qaeda’s military operations chief in Pakistan, shoot down the plane carrying Obama.

The aspirations never developed into further planning, the U.S. intelligence service told The Washington Post.