Who would believe that last week, we would be remembering the horrific events of 20 years ago when America came under terrorist attack on September 11, 2001.

The shadow of those tragic events that still looms large over the world with the invasion of Afghanistan and Iraq, the Arab spring and other such events that have truly impacted upon us in the Western World in the shape of Islamic extremism through Al Qaida and the Islamic State in Syria. We are, of course, still in the middle of the impact with the emboldenment of nations as we see the western world’s pitiful withdrawal from Afghanistan as nations become more introverted as evidenced in the US with the withdrawal and The UK’s exit from Europe.

I remember that Tuesday as do most of us that were conscious of the events on that day. I had just returned from a long weekend and was sitting in London in my office in the Old War Office building when one of my team ran in and said “Boss you won’t believe it, a plane has just flown into the World trade Centre.” I switched on my television and watched aghast as another aircraft flew into the South Tower. And then I saw the fortress that I had visited on many occasions previously which was the Pentagon struck by another attack.

At the time I happened to be responsible for Counter Terrorist Intelligence in the Ministry of Defence. My feet did not touch the ground for the next three weeks from briefing ministers, senior officers, writing papers for and briefing the Prime Minister and number 10 to the Joint intelligence Committee and The Cabinet in the Cabinet Office Briefing Room (COBR). We worked 18-hour days, 7 days a week as the UK’s political machinery began to digest the true impact of the events of 9:11 and prepare itself for other such attacks. I was on one of the very earliest flights to the US after the flying ban had been lifted to share intelligence with our US allies and still remember the stench of burning and aircraft fuel that pervaded the whole of the Pentagon. Even the street lights that had been knocked down at an ever-decreasing level by American Airlines flight 77 until the plane impacted.

Despite the horror of the event it was, I think, one of the most exciting times of my professional career as I lived in history. I saw the machinations of a government in crisis and the full power of the western world impact upon a nation many miles away that had chosen to harbour and develop terrorists for years. Those memories will stay with me forever and those incidents truly shaped my life.

I chose to continue working in counterintelligence from thence on in my military career until I commanded two separate units. I was seconded to Thames House and MI5 in 2002 and the CIA at the National Counter Terrorist Centre in 2005. I was one of the key instigators and first incumbents in JTAC, the Joint Terrorist Analysis Centre.

As I look forward I worry about the future as the German philosopher Georg Wilhelm Friedrich Hegel, a founding figure in German idealism and a historicist philosopher, states “What experience and history teaches us is that people and governments have never learned anything from history or acted upon principles deduced from it”.

Will Afghanistan return to haunt us as a breeding ground for future Islamist extremism? Will the western world’s return to isolationist policies centred around nationalism lead us into greater conflict as environmental factors such as pollution, access to water and clean air become things to fight over?

However, wherever there is hope there is life as Stephen Hawking said: “However bad life may seem, there is always something you can do and succeed at. Where there’s life, there’s hope”.