Terrorist whose real weapon was his voice

He was designated a "global terrorist" but Anwar al-Awlaki's greatest weapon was not guns or bombs but the power of his words.

Anti-Western vitriol poured from his internet sites, Facebook page, booklets and CDs, recruiting many of the foot soldiers responsible for al Qaeda's most shocking operations in recent years.

Two of the 9/11 hijackers attended his sermons and US army psychologist Major Nidal Malik Hasan had been receiving religious advice from Awlaki by email before he ran amok at a Texas military base in 2009, killing 13 and injuring 30. Umar Farouk Abdulmutallab was instructed by him before trying to blow up a transatlantic flight on Christmas Day in 2009.

His internet lectures were blamed for inspiring Roshonara Choudhry to stab east London Labour MP Stephen Timms.

It was this power of oratory as much as his leadership of the Arabian Peninsula offshoot of al Qaeda that caused him to be the only man named as a major threat when the new head of Britain's Secret Intelligence Service gave his first public speech last year.

His ability to convert people had been partly learned in London in 2002. There he found figures such as Abu Hamza openly preaching support for al Qaeda with the authorities taking little action.

Awlaki spent several months giving a series of popular lectures to Muslim youths - many of whom followed him until his death.