How do you stage a concert work? How does a piece without any narrative work when put on an opera stage with sets and costumes? Staged versions of pieces like Handel’s oratorios have become commonplace, but there is something different about Benjamin Britten’s War Requiem, not to mention Catalan director Calixto Bieito’s staging of it. It is a piece that resists easy categorisation, part mass, part song cycle. In the hands of Bieito, it is still – if not more –difficult to categorise, but in staging it, he creates a challenging, striking, frighteningly intense spectacle, making the outcry against war even louder.

Britten wrote his War Requiem for the consecration of the rebuilt Coventry Cathedral in 1962, after the old cathedral had been bombed by the Luftwaffe in 1940. As well as being a setting of the Requiem mass, Britten also incorporated poetry by the English poet Wilfred Owen, commenting on the mass text. Bieito bases his staging of the War Requiem on a story his mother told him as a child, of a congregation trapped inside a church during a bomb attack on their village. This story serves as the starting point for the staging, using Coventry Cathedral as the scenic backdrop.

Susanne Gschwender’s stark sets place the action inside a church – Coventry Cathedral – yet serve as reminders of the artifice of theatre. Giant scaffolding surrounds the pews and huge stained glass window; it even contains the chamber orchestra. Despite this insistence upon artifice, everything taking place on stage feels so uncomfortably close, so real. Even though the confines of a church made the time and place concrete, the happenings inside were abstract, not necessarily dependant on the locale of the church.

Bieito doesn’t follow a strict narrative in his staging, rather letting the action on stage follow and comment on the music. The tenor and baritone soloists are soldiers – dead or alive, it does not matter – reliving their experiences on the battlefield. The chorus are churchgoers, subjected to a bombing attack that in the end maybe kills them. The soprano soloist seems to take on the role of worship leader, one of crazed, almost prophetic, spiritual clarity, like an infanticidal Cassandra, directly from the pages of Greek tragedy. Bieito’s staging is one of ambiguity and uncertainty, leaving the audience to create a story themselves, if one even is needed.

There is not much hope in this War Requiem. As Owen’s The Parable of the Old Man and the Young comes to a close, the tenor and baritone singing of Abraham slaying “half the seed of Europe, one by one”, the strikes of the chamber orchestra are made all the more chilling when members of the children’s chorus fall lifeless to the ground. The horror and violence of the Libera me, by the end a huge, unrelenting wall of sound, is only made more all the more severe by the concluding, calm, yet uneasy In paradisum.

The deeply unsettling stage action did not – perhaps surprisingly – take attention away from the music. Instead, it reinforced it, made it ever more visceral and uncomfortable. The chorus, almost double their usual size, sang as if their life depended on it. Although sounding somewhat wobbly at the very beginning, they moaned, wailed, whispered with utter conviction. Rarely have I heard them sing so softly, so loudly, sounding so beautiful, yet so ugly.

The three soloists were similarly impressive, in both their conviction and their musicality. Soprano Natalia Tanasii was devastating to watch, as a mother turned mad with grief, or a crazed faith leader, prophesising the end of the world. Tenor Evan LeRoy Johnson, in his debut performance of the War Requiem, sang with astonishing sensitivity, bringing both fragility and power to the high-lying part. His final duet with baritone Johannes Kammler, a setting of Owen’s Strange Meeting was filled with an otherworldly sadness.

The two orchestras, the full-sized one in the pit and the chamber orchestra on stage, led by Lothar Koenigs seemed to become one with the singers. The chamber orchestra impressed with especially fine string and harp playing, while the pit orchestra followed and led in equal measure the chorus and soprano soloist, letting loose shockwaves of sound without being overpowering.

Bieito’s frighteningly intense War Requiem is going to stay with me for a long time. But what I think will stay the longest is the very ending: having witnessed the carnage on stage, a little boy dons a military uniform, and as the chorus sings of heavenly angels and eternal rest, he puts on the helmet. He will have no rest. The violence begins again, corrupting a new generation.