‘Our lives are pointless, so our deaths are pointless,’ sings Caligula, as his terrified subjects dine with him, turning a blind eye to the rapes and murders he commits in their presence. And Peter Coleman-Wright’s Caligula is a terrifying force, mad, amoral and apparently unstoppable.

It starts in silence, with a hand around the lush velvet curtains of the Coliseum. A dishevelled Caligula emerges to stare at us. Behind the curtains, a bank of seats faces us, orange plastic stadium seating, empty. Then the work begins with Caligula’s anguished shout, tortured strings and a high, screaming wind section over kettledrums like a racing heart. And the heartbeat is a theme that runs through the piece, forcing us to stay inside the madman’s view of the world, sharing his crisis of the meaninglessness of everything – after the death of his sister Drusilla, who haunts the stage as a veiled, naked figure.

Some dictators appear onstage as charismatic figures, drawing us along till we are horrified at our own capacity to consent to their domination. This one is different. True, those around him are paralysed by inaction, at one point echoing Waiting For Godot – ‘What are we waiting for? ... We’ll wait for ever.’ ‘Indeed we will’. But we’re not invited inside their minds or souls.

Caligula keeps asking his slave Helicon (the magnificent countertenor Christopher Ainslie) to bring him the Moon. He looks at himself in a round mirror that grows bigger throughout the opera till he can hold it above his head and look back at the entire audience, as if hanging above the world, looking down. He is utterly disengaged from reality, at one point staging a performance playing Venus like a grotesque pantomime dame.

Clearly, he is mad. And clearly, as body bags pile up and terrified citizens pay homage, a lethal dictator. But it is his deranged view of the world that we’re invited inside. He keeps telling himself to be logical, as if the only logical outcome of life’s lack of meaning is meaningless death, inflicted on a whim. But the music belies this madman’s world where nothing matters. The heartbeat, sometimes more like marching boots or the feet of a running crowd, is a visceral common rhythm. Jagged brass and lyrical strings take us into both the madman’s anguish and the horror he’s inflicting around him. Full of passion, warmth and humanity, it asserts our capacity to feel and to care what happens.

Yes, the passive Romans who never act against their dictator are culpable. But Caligula’s murderous madness is also a horrible warning of what a world without meaning looks like.

Till June 14 June 2012