WHEN we left Martin McDonagh’s last play, the actors were taking a slithering curtain call in the pools of stage blood left by their arm-loppings and spine-choppings.

But The Lieutenant of Inishmore was set in the extreme West of Ireland where, as McDonagh has shown us in all his work to date, extreme callousness takes extreme forms. How would his dark, dangerously funny muse react to being transported for the first time outside the Emerald Isle?

Well, you have only to see the curtain rise on his Pillowman, revealing David Tennant’s short-story writer sitting hooded in an interrogation room in what the programme says is a totalitarian state, to know that your stomach will be churned. And you only have to hear Jim Broadbent’s Tupolksi, good cop to Nigel Lindsay’s bad cop, to know that black comedy is in the offing. “It feels like school somehow,” Tennant remarks nervously. “Except that at school they didn’t execute you at the end,” Broadbent chuckles genially.

Yet this is a very different McDonagh play. That’s not to say there isn’t violence and ugliness, because there is, including some Grand Guignol torture and a mimed crucifixion. There’s plenty of gallows drollness, too. But the play doesn’t make the expected progression into McDonagh’s version of Pinter’s One for the Road, with Tennant’s Katurian physically and morally destroyed for the crime of being an intellectual.

No, McDonagh’s first surprise is that the trouble isn’t political at all. Rather, it’s that Katurian’s weird, disturbing stories obsessively concern hurt, maimed, murdered children, and that there have been killings that ape them. And the next surprise is that McDonagh’s subject isn’t cruelty or pain per se. Rather, it’s art and, dare I surmise, his art.

It would be impertinent to wonder what lies behind McDonagh’s suggestion, vividly conveyed in a silent scene staged above the interrogation room, that writers should experience personal and preferably childhood horrors if not to become terminally bland.

But when Katurian’s damaged, adoring brother turns out to be the copycat killer, it’s reasonable to ask if McDonagh, who has often been accused of exulting in horror, isn’t asking himself some tough questions. What is the effect of gruesome stories or, indeed, McDonagh’s own plays? Can art corrupt?

Add the idea that surfaces as Katurian nears his end — maybe art matters more than any life including the artist’s — and you have an intelligent play that’s sometimes marred by flippancy and folly and gets repetitive, but is well enough acted to maintain a grip.

Tennant could be more scared, given the proximity of electrodes and the Grim Reaper, but Broadbent is wonderfully teasing and witty as the soft cop who isn’t, and Adam Godley, playing the brother, offers a superb case study of grown-up infantalism. Altogether, an unnerving but provocative evening.

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