Written by Billy Barrett, Joe Boylan, Craig Hamilton, Ellice Stevens, Victoria Watson 

Directed by Billy Barrett & Ellice Stevens

Cast: Joe Boylan, Craig Hamilton, Sophie Steer, Ellice Stevens

Watching Tank is an unforgettable experience: a disorientating fusion of stage, screen and radio full of daft humour, cold cruelty and brilliant performance, it’s almost as bizarre as the Cold War research project that inspired it.

Breach is a company known for exploring modern history in its work, and this time the subject is a NASA-funded experiment that, for most of the 1960s, tried teaching dolphins to speak English.

Goofy as this may sound, it’s a story of colossal arrogance and waste, inhabited by intelligent people with no apparent empathy or compassion. The brilliance is in the way the four actors tell that story.

It’s mischievous and immersive. The actors don’t even acknowledge the fourth wall, introducing themselves and the characters they play directly to the audience, handshakes and all. Much of the time they perform verbatim accounts from humans and dolphins alike of life in the Caribbean research centre. At other times they are narrators, sometimes winking to the audience as themselves and sometimes providing cheesy voice-overs to the action onstage or on the huge screen dominating the back of that stage.

Margaret Howe, the reedy college drop-out who arrives at Dolphin House as a volunteer is played by Sophie Steer with a sad, unknowable air. Joe Boylan plays Peter, the dolphin with whom she forms an extremely close bond. There are no awkward animal impersonations. Boylan gives us a dolphin in human form, full of physical grace and power with emotions and intelligence he’s unable to express verbally, however strenuously the humans goad him. It’s an extraordinary performance: energetic, frightening and tragic.

Much of the interaction between Margaret and Peter is seen silently in deep blue water on the screen while they simultaneously enact more vocal, personal moments on the stage. Rather than dividing the attention this proves highly effective, never more so than when Dr John Lilly decides Peter the dolphin should be injected with LSD for reasons that doubtless made sense to him at the time. Lilly is a study in academic conceit from Craig Hamilton, who makes him an aloof, self-absorbed enigma; an Andy Warhol of scientific abuse funded by the taxpayers of America.

All other intelligent mammals are played by the cheeky and versatile Ellice Stevens. In a climactic scene of near-unbearable strength, she and Hamilton carry on a conversation of half-baked theories and half-grasped facts while Peter the dolphin dies slowly in a claustrophobic tank of his own waste. It feels like overhearing two ignoramuses on social media or public transport but being unable to interrupt or escape the stream of hateful nonsense, and Joe Boylan maintains his astonishing silent performance for the duration.

It defies belief that people who must have spent more time with dolphins and knew more about them than almost anybody else on the planet could have been oblivious to the fact that they were torturing the highly developed creatures in their care. Although it’s an unflinching exposé of institutionalised cruelty, Tank makes no overt comment on the ethics involved, leaving the audience to judge the humans on their actions and motives. It’s one reason why the play never feels didactic and allows it to be so funny a lot of the time. This is a compelling hour of inspired storytelling, fractured and frantic but full of compassion. It’s the performances that stay longest in the memory, particularly the unrelenting energy and sensitivity of Joe Boylan.

Tank by Breach is on at HOME in Manchester until Saturday 6th May 2017, after which it can be seen at Birmingham Rep and OFS in Oxford.