The president was concerned by a lack of strategy at his first meeting with Gates and the US joint chiefs of staff last month in “the tank”, the secure conference room in the Pentagon. He asked: “What’s the endgame?” and did not receive a convincing answer.

Larry Korb, a defence expert at the Center for American Progress, a Washington think tank, said: “Obama is exactly right. Before he agrees to send 30,000 troops, he wants to know what the mission and the endgame is.”