Osama bin Laden banned al Qaeda from assassinating Joe Biden because the Democrat would become an incompetent president and ‘lead the US into a crisis’ if jihadists were successful in killing Barack Obama.

Bin Laden made the remark in a 2010 letter that was found in a trove of documents at the Pakistan compound where he was killed by US special forces in 2011.

The document was first made public in 2012 but has been brought back to light and given new significance amid the chaotic US withdrawal from Afghanistan that has gifted the country back to the Taliban.