The sex scandal that brought down David Petraeus poses a tricky dilemma for his old foes in the Taliban: should an adulterer be stoned to death or executed by a firing squad made up of his mistress's relatives?

As generals, journalists and military analysts in the United States continue to ponder the national security and political implications of Mr Petraeus's spectacular fall from grace, his affair and resignation have tickled the famously humourless Taliban.

"From a Pashtun point of view, Petraeus should be shot by relatives from his mistress's family," the Taliban official explained helpfully.

"From a sharia point of view, he should be stoned to death."