Who is the angriest British dramatist now putting pen to paper or hand to computer? Well, I could cite an alienated young turk or two — Martin McDonagh isn’t exactly at peace with the world — but I can’t think of a single one whose work radiates the quiet fury that’s articulately pouring from the 68-year-old Caryl Churchill. Back in 2000 she gave us Far Away, which started with tales of violence and ethnic cleansing and ended with a fearsome vision in which the entire human, animal, vegetable and mineral world had been transformed into combatants, weapons or both. But that armageddon was set some years in the future. In her new hour-long play the political evils are recent, current or impending. They’re also specific, for their source is an America that Churchill sees as irredeemably selfish, arrogant, callous and ruthless — and is obsequiously supported by a lackey nation that’s clearly Britain. James Macdonald’s production begins gently and deceptively, with Stephen Dillane’s indolent Jack, who is English, tipsily admitting to Ty Burrell’s nervy, driven Sam, who is American, that he’ll love him for ever. And across the Atlantic the two men huddle together on a floating sofa and chat, canoodle, quarrel, make up and generally act as if they’re having a love affair.

But we soon realise that this is a very symbolic affair, not to say a pretty Special Relationship. Sam (as in Uncle) and Jack (short for John Bull) discuss subjects from Vietnam to Iraq, torture to rendition, and when Sam demands “commitment” from Jack he’s demanding unquestioning agreement with the views of Globocop. Bush and Blair in sexy cahoots, then? Perhaps partly. But Churchill’s focus and target is America’s broader foreign policies and Britain’s supposed complicity in them. The pillow-talk embraces US- supported dictators and death- squads, black propaganda and fake elections, napalm on Vietnam, the genocide of native Americans and the bombing of civilians in war-zones today, and much, much else. Occasionally Jack dares to demur, as when US protectionism or global warming enters the sensual equation. But since Sam regards disagreement as treachery, he usually backs down, much as (in Churchill’s view) Britain does when America throws its weight about.

It’s clever, gripping stuff, but so ferociously one-sided it had the perverse effect of making me, aghast as I am at the neocon blunders and escalating horrors in Iraq, feel like defending America. Doesn’t Churchill indiscriminately badmouth the nation that conquered Hitler, created the Marshall Plan and (recently) ended the Serbs’ war crimes in Bosnia? Surely there must be one foreign country, and Churchill names dozens, that hasn’t suffered from America’s iron fist, dirty tricks or its pushy definition of democracy and freedom?

Still, this is how more and more Britons are feeling, and maybe the best way to see Churchill’s play is as a phenomenon: a very topical manifestation of mistrust, anxiety and, yes, anger.

Box office: 020-7565 5000