One of the great perks that comes with singing with the London Symphony Chorus is the opportunity to travel widely, both within the UK and around the world. Over the years the choir has travelled extensively (from Cardiff to Kuala Lumpur, from Newbury to New York) and sung in a variety of stunning and not-so-stunning venues. I remember singing Britten’s War Requiem in the open air in Athens, for example, and singing the first choral concert in the concert hall in Kuala Lumpur’s new Petronas Towers. I also remember singing in Italy in a “converted” sports hall where you could still see the lines of the basketball courts on the floor.

In September 2001 I joined the choir in a modest trip (out one day, back the next) to Ghent in Belgium, where we were due to sing Verdi’s Requiem as part of the Flanders Festival. On the afternoon of 11th September we gathered in the city’s majestic Gothic Cathedral to rehearse with the orchestra and soloists ahead of the evening’s concert.

Verdi’s Requiem is a piece we have often sung and which never loses its depth and grandeur, perhaps because we have been so well trained over the years (by our good friend Sir Colin Davis) to be fully aware of piece’s invocation of death and – worse still – of the fear of death. It is a piece that never fails to move me.

Our rehearsal started well enough as far as I remember. The memory that stands out most begins with the moment when I began to be aware of an unusual level of extra-curricular activity amongst members of the orchestra, who were handing round mobile phones, sharing I-knew-not-what information. By the time we reached our mid-rehearsal break we were all aware that something was happening in the world beyond the cathedrals walls.

I remember the buzz and rumour that broke out as we left the cathedral in search of drinks – and of television screens. I remember watching live images of smoke pouring out from the upper floors of New York’s Twin Towers. It was hard to believe that this was real and not some futuristic horror film.

With the benefit of hindsight, I wonder how these images affected the many Westerners who viewed them and how this compares with the impact of images of disasters from many other parts of the world, especially of what we have come to know as the “third world”. For surely the impact of these images lay, in part, in the way we recognised the Twin Towers as a symbol of our Western lives. These questions were not in my mind at the time, however, as we watched the events unfolding in mute disbelief.

I’d like to say that I vividly remember the concert with the music’s powerful invocation of death. The truth is that my memories are overlaid with the impenetrable veneer of the shock and disbelief we were all experiencing on that evening of 11th September, 2001.

This was the day that became known as 9/11.