Ali Soufan is a former FBI special agent who for many years was as close to the heart of the US government’s shadow war against Al Qaeda as it’s possible to get.
However what sets him apart is that he was pursuing the top leaders of Al Qaeda, both before and after September 11th.
It’s a perspective that has given him a rare insight into how the organisation founded by Osama bin Laden has persisted and in fact grown many years after its demise and death was announced.
Speaking to ITV News in London, Mr Soufan said that Al Qaeda is larger, more widespread and more dangerous at any time since 9/11.
At the time of the attacks on New York and Washington, Mr Soufan said, Al Qaeda had a membership of 400 and was located only in Afghanistan.
Today it has thousands of battle-hardened members in affiliated groups stretching across South Asia, to Somalia and Kenya in East Africa - all the way to West Africa - and of course in Western countries too.
During his time at the FBI, Mr Soufan was instrumental in the questioning of Abu Zubayda, and Al Qaeda commander, whose information led to the identity of Jose Padilla, a US citizen who was convicted on charges of aiding terrorists.
Mr Soufan said Al Qaeda had learned to develop in new ways and through new and more dangerous spin offs: “The cancer of bin Ladenism has metastasized across the Middle East and North Africa and beyond, carried by even more virulent vectors.”
Mr Soufan points to the invasion and war in Iraq and the Arab Spring as two seismic events which proved seminal in how Al Qaeda had developed and grown and led to the growth, in particular, of so-called Islamic State.
He also acknowledges that how the so-called War on Terror was damaging. In particular, the use of rendition, CIA run black sites where torture and so-called “enhanced interrogation” was used on Al Qaeda suspects, which helped Al Qaeda radicalise a new generation of followers.