It has been exactly 25 years since a National Theatre revival put Githa Sowerby’s play back on the theatrical map. Written in 1912, it is now firmly established not just as a landmark of Edwardian feminism but as one of the most durable plays of the last century, comparable to the best of Harley Granville-Barker and DH Lawrence. Though I have a few cavils about Polly Findlay’s new production, it still makes a powerful impact thanks, in no small part, to Roger Allam.

Seeing the play again, I am struck by Sowerby’s synthesis of socialism and feminism. Her protagonist, John Rutherford, is the patriarchal owner of a Northumbrian glassworks whose world is crumbling and who succeeds, in the play, at alienating all of his family. One son, John Jr, is cheated out of an invention that may save the tottering firm. Another, Richard, is a despised cleric who takes his pastoral mission elsewhere. Janet, the 37-year-old daughter, is banished for supposedly sullying the family name. That leaves Rutherford with a daughter-in-law, Mary, who proves to be pivotal and have unexpected agency.

Sowerby’s great gift was for capturing a world in transition. Rutherford’s domestic tyranny is challenged just as in society the idea of a predominantly male suffrage was under threat. But Sowerby – as Patricia Riley’s admirable biography, Looking for Githa, makes clear – also knew all about the working world she depicts. On the one hand, industry is seen as a Moloch that requires human sacrifices. On the other, Sowerby reminds us this is a time of union militancy, new inventions and increasing American competition. It is that ability to pin down a moment of historic change that makes this play an important social document as well as a first-rate drama.

My doubts about Findlay’s production can be quickly stated. She and designer Lizzie Clachan swathe the play in “atmosphere” – it begins and ends with curtain-rods of rain – missing the visual clarity of the recent Sheffield Crucible revival. Findlay is also so anxious to establish the play’s roots in north-east England that, in a couple of cases, the actors’ accents are hard to follow.

That is emphatically not the case with Allam, who is magnificent as Rutherford. He presents us with a man who rarely shouts or blusters because he exercises power as if by divine right. But, while embodying a capitalist patriarchy, Allam indicates Rutherford’s moral vacancy: when he tells his clerical son, “You might just as well never ha’ been born,” it is with the casual indifference of a man enslaved by the profit motive. Allam also subtly suggests, when he nervously withdraws his hand from his foreman’s shoulder, a man terrified of physical contact.

It is a richly detailed performance and Justine Mitchell is equally excellent as the daughter who rebels against years of servitude by passionately attacking her father’s values. Sam Troughton memorably lends the mutinous John Jr a touch of nervous hysteria in demanding a reward for his promised invention and Anjana Vasan as the daughter-in-law perfectly captures a decisive change in the domestic and industrial balance of power. If any Edwardian play has stood the test of time, this is unforgettably it.

• At the Lyttelton, London, until 3 August.