Geoff Morrell, the Pentagon spokesman, said: “Despite some sensational speculation by one of the London papers, I can assure you General Petraeus is not quitting as Isaf commander, but nor does he plan to stay in Afghanistan for ever.

“Obviously he will rotate out at some point, but that point has not yet been determined and it will not occur any time soon. Until then, he will continue to ably lead our coalition forces in Afghanistan.”

By the end of the year, Petraeus will have done 18 months, a normal rotation for the post, and he would be in the running for a more senior post back in the US.