Jonathan Holmes’s powerful “verbatim play” begins and ends with Condoleezza Rice. Interviewed by al-Jazeera after 9/11, she declares that America is launched on a war against terrorism whose aim, like that of Islam itself, is “to protect the innocent”. Four years later she’s in a Presbyterian church, thanking God for looking after the American military as well as “those innocent Iraqis who suffer at the hands of these senseless killings by people who are trying to shake our will”.

But in between Holmes’s “verbatim play” – meaning a docudrama consisting of the private and public words of those Americans and those civilians – suggested that the events in Fallujah make My Lai in Vietnam look like an unruly clambake. The accusation is the one Tacitus made 1,900 years ago: they created a wilderness and called it peace.

It’s hard to review stuff like this. Indeed, it’s less a play than a sort of tribunal vivant whose evidence shocks and disturbs but hasn’t the authority of something that will never occur: an investigation by disinterested international figures into allegations of American atrocities in 2004 Fallujah. Just as you can’t indict Tony Blair for criminal warmongering on the basis of Called to Account, the hypothetical court case also playing in London, so you can’t be sure that the evidence assembled here isn’t selective or unreliable.

But you’re left feeling that there’s a case to answer. Were the brutalised bodies of contractors whose discovery outside Fallujah precipitated the siege and attack actually those of mercenaries? Were women and children asked to walk to a mosque with white flags, only to be shot by Marine snipers? Was the American general who denied using napalm actually using the deadlier Mark 77? And is the British major interviewed by Harriet Walter’s reporter right when he accuses the Americans of disproportionate, indiscriminate, counter-productive violence against people they regard as untermenschen?

Walter’s Sasha, who ends up vomiting in horror at slaughtered babies, is more or less omnipresent. So is Imogen Stubbs’s Jo, an aid worker who can’t understand why the Americans persistently attack her ambulance. They and the rest of Holmes’s cast certainly hold the attention of spectators, who are also promenaders, patrolling the innards of an old brewery that’s weirdly crammed with anticontamination suits – and, of course, fiercely dramatic scenes.

Myself, I’ll remember Walter’s pain and the bewilderment of Stubbs and her equally plucky colleague, Shereen Martineau’s Rana; but also the lieutenant who says that 9/ll justifies the killing of unarmed families, the sniper who describes his work as “heaven”, the Marine who says that the Gulf couldn’t wash away the blood he’s seen. But shouldn’t Holmes have acknowledged their fear as well as their rage? We must leave it all to history, which, as usual, will lie.

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