Los Angeles-based composer David Lang wrote the score for the hit films La Grande Bellezza and Youth, but when he comes to London this week it is to hear a very difference composition of his sung at the National Portrait Gallery.

The Portrait Choir, joined by other communities choirs, performs his Memorial Ground, a deceptively simple "hymn" that commemorates those whose lives were lost in the first world war, and since, and those who survived but whose lives were changed for ever.

Memorial Ground allows the singers at the many performances that have taken place since its premiere in Scotland in July to add family or personal recollections of their own, sung to a tune by Lang, but repeating as many notes from his score as is needed to name individuals and sum up what war did to them.

The choirs will also sing Sir Hubert Parry’s elegiac Songs of Farewell and poet Jackie Kay will read her poem Private Joseph Kay.

Admission is free, but booking beforehand is essential. Click here for more details.