Waste (Lyttelton Theatre, National Theatre)

The story at the heart of Harley Granville Barker's Waste – that of a political idealist brought low by scandal – has not dated one jot since the day it was written in 1907 or indeed since its first performance in 1936.

The delay was caused by the Lord Chamberlain – to whom all new plays had to be submitted until 1968 – objecting to the play's "extremely outspoken reference to sexual matters," and the mention of an abortion. He really meant these matters insofar as they affected the ruling class, of course.

In between the writing and the performance, Barker made a new version altogether, and Roger Michell's handsome revival, played in period costume on Hildegard Bechtler's stark abstract set of giant moving panels in discreet blues and greys, plunders both versions, as did John Barton's great revival at the RSC in 1985.

The result is a long (nearly three hours), fairly prolix evening of drawing room social banter and political skulduggery as Henry Trebell (Charles Edwards), an Independent MP, does a deal with the Tories to push through a bill to disestablish the Church from the State and realise his vision of churches turned into new schools. It's as though Nick Clegg had combined with Michael Gove on a coalition plan of free schools in empty places of worship.

Granville Barker also drew on the late 19th century scandal when the Irish nationalist leader, Charles Parnell, was revealed to have fathered children with a married woman, Kitty O'Shea. Here, the upstanding Trebell is seduced in the moonlight by Olivia Williams's siren-like Amy O'Connell, also Irish and married; the devastating twist here is that her husband, Justin O'Connell (Paul Hickey), is a Fenian activist recently interned by the incoming Prime Minister.

But even the Home Rule issue is trumped by another trigger to tragedy, a scandalous backstreet abortion. At the same time, insofar as this affects him, Edwards makes things worse for Henry, and more intriguing for the audience, by playing up the cold fish side of his character’s nature.

"A man of ideas is often an embarrassment to the government" was another line that went down well – Lord Kinnock, who has informally advised on the production, meeting the actors in rehearsal – had a good chuckle, too, further along my row. But the laughing stopped dramatically on the opening night when an elderly member of the audience in the front of the stalls keeled over with an ominous groan.

The play resumed for its final few minutes half an hour later, adding a terrible poignancy to the onstage regret at Trebell's fate and the waste of a good life. "Life for its own sake is overrated" was an appropriate sentiment all round; parliamentary systems are nothing unless they sustain and improve the material and spiritual welfare of their constituents.

The play opens with a jovial discussion about the political theorist Walter Bagehot in the country home of Lady Julia Farrant (Lucy Robinson). Other denizens include Doreen Mantle's funny old Lady Mortimer and Trebell's devoted sister Frances (played with a refreshing, open-faced candour by Sylvestra Le Touzel).

Chopin's salon piano music, mostly the Preludes, is distorted through a strangulating sound system by John Leonard, a brilliant touch, and we see why when the assembled politicos – including Michael Elwyn's dithering PM and Gerrard McArthur's sharp-edged dissenting partner in Trebell's reform plans – get down to business and close ranks. But although the bleak awkwardness of the Lyttelton is partly redeemed by Bechtler's design, I still don't like the membrane of microphone on the actors' voices.

Waste runs at the Lyttelton (National Theatre) until 19 March.