The lout Rea plays—Eric, a British loyalist whose irrational hatred of the IRA and Irish Catholics in general, whom he calls Fenians, has twisted his sanity and turned him into a raving maniac—is an ignorant xenophobe, whose specific malady (the play opens with him asking Bridget, a psychiatrist, why she’s an “n” word) is a casual racism that Ireland hopes initially shocks us, but that’s nothing compared to what he gives us next. It’s not giving anything away to say that Eric decides that his newborn granddaughter Mary May—whom his wife Bernie and daughter Julie dote on—looks exactly like bearded, bespectacled Gerry Adams, former head of Sinn Fein.

That’s not a joke; it’s the unfunny truth. As Eric’s actions get more frenzied and paranoid, one wonders why nobody calls the loony bin before it’s too late, especially after Julie finds her daughter sporting Adams-like glasses and a drawn-on beard that Eric did himself. Some of this is amusing in a superficial, “is he really going there?” sort of way, but once it’s obvious where Cyprus Avenue is heading, it becomes quite enervating to watch someone so cartoonishly realized for our superior amusement (if not bemusement).

That negative reaction comes in spite of Rea’s splendid performance. There may be no other actor who could play this ludicrous character and make him watchable and even (almost) sympathetic, but Rea does it with effortless charm, even in a long, desultory back-and-forth between Eric and a loyalist paramilitary who first thinks our protagonist might be Fenian. Preceding that scene, Rea transfixes us in an amazing if muddled and drawn-out monologue about the Troubles (“But then came Riverdance and Liam Neeson and U2. And now it’s all grand to be Irish, it’s all fine”).

The other performers are fine, Vicky Featherstone’s direction is as focused as can be expected of such dramatic dead weight dropped on our toes (although she can do nothing to make the bloody—and bloody pointless—finale provide much more than a cheap shock effect, or two, or three), and Ireland has a way with a funny line or rant. But Cyprus Avenue, even with Rea’s expert guidance, ends up at a dead end.