Howard Davies’s revival of The Plough And The Stars opens with a handyman working on the door of a Dublin tenement room. This might seem only prudent, as the last time he directed a Sean O’Casey play on the National Theatre’s Lyttelton stage, the opening night ground to a halt for several minutes when such a door stuck shut. But no, it’s in the script of this play after all (which Davies co-directs with Jeremy Herrin). And this is a play that puts O’Casey among the great dramatists of the last two centuries.

In April this year Ireland commemorated the centenary of the Easter Rising, which failed in itself but laid the foundations of Irish independence five years later. July saw the centenary of the beginning of the Battle of the Somme, one of the bloodiest engagements in history. The timing of this opening alludes to both: the play depicts the inhabitants of a tenement building during the Rising, one of whom is an embittered Unionist widow who has recently lost her son on the Western Front.

I make the evening sound grim. It is, but not unremittingly. O’Casey’s skill, which reaches its zenith here, is in showing how absurd the lives of these Dubliners can be, yet without shading into ridicule or contempt. He lets drama and humour clash against one another. Act two is punctuated by extracts from the speeches of iconic Irish republican Pádraig Pearse... but those are in the background, outside the window of the pub within which bitchery and brawling dominate. Even in the third act, as things get serious with gunfire in the streets, the folk here are principally dodging the bullets on their way to loot the shops.

But the fourth and final act is harrowing, with two deaths offstage – both predictable – and a third on – shocking in its suddenness. This, too, is part of the lives of O’Casey’s characters, and it is bearable – if it is at all – only because Irishness is the passionate core of their identity. For all their foibles and shortcomings, he loves and respects them without reservation.

Although they’re not the biggest characters, the focus of the drama is on Jack and Nora Clitheroe, he an idealistic officer in the rebel Citizen Army and she haunted with expectations of the worst for him. If Fionn Walton is compelling as Jack, Judith Roddy’s Nora is electrifying. Vicki Mortimer’s sets of crumbling masonry and James Farncombe’s grimy, brooding lighting set the tone for an evening of uneasy viewing, especially for English theatregoers, but essential theatre.

Written for The Lady.