9/11 was a day that changed the world, and even though we are 3,000 miles away from New York, we have been living with the consequences for the last 20 years.

Anniversaries are important as that they remind us of events: the terror of the moment; the horror of the lost lives.

There was the uncomprehending realisation that there were terrorists who were prepared to kill themselves in order to further their desire to take thousands of civilians with them. 9/11 made the world feel suddenly vulnerable and unsafe, but immediately you could feel America was united in a determination to make itself secure once more and to even the score.

You have to remember those emotions if you are to understand the subsequent events of the last 20 years.

But can we say we have had success in the last 20 years? America’s has not suffered a repeat atrocity, but everyone everywhere, from the Bataclan to the Manchester Arena, has been touched by terrorism.

Boris Johnson says today that the terrorists failed to break the principles of the western world, which is true, but we’ve come pretty close in Guantanamo Bay, for example.

And our hurried exit from Afghanistan has returned the Taliban to power and made anyone minded to work with us unlikely to do so because they now know we could abandon them. The world does not feel any safer than it did in those horrifying minutes as we watched 9/11 unfold on our television screens.