The most infectious feature of Kieran Knowles’s debut play is the tight amity and paced unity of the cast that is matched by the inherent camaraderie in the plot. Operation Crucible refers to the sustained seven-hour bombing of Sheffield in 1940 – a blitz that all but destroyed the steel city. We follow four steel workers as they remember the course of their lives leading up to that event, through banal experiences of normality – traditions, family, work, falling in love, domesticity, loss, indirection and community life – until they reach the apex of war. Knowles impeccably balances the sense of unity: the representation of an entire nation with the individual voice and a reminder of the genuine humanity of those who endured and lost.

The narrative and Bryony Shanahan’s direction follows a pattern that alternates between oppositions, that keeps the audience’s heart in their throat and emotions on the surface of their skin. There’s apprehension: slow and threatening apprehension, like the looming danger of wartime, quietly ticking its way up to crescendos of deep-felt anguish and intensive pain. The front row finds itself in the direct firing line as playful reminisces turn into hell on earth. There is a definitive rhythm to the text as it undulates through pacey and energetic highs and despairing lows.

All of this is on the shoulders of four actors, but those actors – though small in number – are big in ensemble. They work in time to reinforce the rhythm of the script and are given definite movements and places within their team. All of this facilitates the pre-set structure, but the actors’ real contribution is to the individuality of the characters. Phil (Paul Tinto) prioritises his wife and baby. He is big and strong with a heart that is even bigger and stronger. His passion has the capacity to become aggressive, but there is an endearing sensitivity to him. Arthur (Jamie Wallwork) has a heritage in steel; his father brought him to the factory as a young boy and the magic from that experience has stayed with him. Kieran Knowles himself plays Tommy, an earnest, warm-hearted loner whose entire life, social and otherwise, is based in the factory. Bob (Salvatore D’Aquilla) is a clueless and socially awkward apprentice. D’Acquilla’s performance is flawless and there is no seam whatsoever between actor and character. He is loveable, hilarious and intensely real. D’Acquilla’s characterisation alone is worth the ticket price.

I came out of Operation Crucible emotionally exhausted and silenced, my heart still jumping, eyes still leaking and giggles still forming. Undoubtedly worth a watch.

Operation Crucible is playing at the Finborough Theatre until 22 August. For more information and tickets, see the Finborough Theatre website. Photo: Ben Macintosh