General David Petraeus, the US commander in Iraq, is to present to Congress his long-awaited assessement of the military ”surge” in Iraq, in which five additional combat brigades were deployed.

Though most experts agree that security in Baghdad has improved since the surge began in February, its overall success is contested. In a letter to US troops ahead of his testimony, Gen Petraeus conceded that the ”tangible political progress” expected from that the surge was supposed to spur had ”not worked out as we had hoped”.