Details of how the US finally managed to track down al-Qaeda’s chief mouthpiece to the West can be revealed today by The Sunday Telegraph, which has learned that the key breakthrough came when CIA officials caught a junior courier in Awlaki’s inner circle. The man, who is understood to have been arrested three weeks ago by Yemeni agents acting for the agency, volunteered key details about Awlaki’s whereabouts which led to Friday’s drone strike as his convoy drove through the remote province of Jawf, 100 miles east of the capital, Sana’a. Told he faced either a harsh prison term or the chance of a new life outside terrorism, the prisoner gave the vital clues that led to the most significant blow against al Qaeda since Osama bin Laden’s death.

“The CIA lifted a courier a few weeks ago and he started talking,” said one senior Western intelligence officer. “The senior al-Qaeda players never give up anything, but the junior ones always talk. The interrogation methods are very sophisticated – there are no thumbscrews or water boarding involved.

“It’s all about striking deals and making the individual understand that his life as a terrorist is now over, and offering him alternatives. The information they gleaned enabled the CIA to mount an intelligence-led kill mission.”