Private Lives: How Noël Coward's drama about champagne-fuelled hedonists retains its cocktail power

As the play returns to the West End, Coward's biographer Philip Hoare looks at how the drama chimes with modern-day audiences

High spirits: Anna Chancellor and Toby Stephens in 'Private Lives' now running at the Gielgud Theatre (JOHAN PERSSON)

Of all Coward's plays, Private Lives remains the most pristine, elegant example of his art. It is deceptively simple. "Minimal as an art deco curve," wrote John Lahr of The New Yorker, "Private Lives matched its content: a plotless play for purposeless people."

In that, the play has the ability to sum up the restless spirit of Coward's era. Private Lives finds its power in the hangover of a new decade, as the 1920s tipped into an uncertain future. This chamber piece seems to exist in a vacuum, a kind of stylised limbo, lacking consequence or context. And yet it also hints at something darker in its characters' interior lives, and that of its creator's – both concealing and revealing at the same time.

Like so many of Coward's plays – and like his own life – Private Lives hides more than it gives away. It says as much in its sly title, and even more so in its intriguing subtitle, An Intimate Comedy. This three-day wonder (the time he took to write it) was Coward's greatest success, earning an astonishing £3,200 for him every week. It made him the highest-paid author in the Western, as well as the West End, world.

Private Lives marked the peak of the playwright's career. It celebrated a new society of meritocracy, a new era of celebrity and success. Yet it was written at a time of economic depression, one which echoes our own straitened times – the play opened in 1930, a year after the Wall Street Crash (and, incidentally, the proposal for a European Federal Union). That sense of conflict and paradox belies the apparent sheen of Coward's play. The deluxe world he depicts is an alternative reality, a fantastical entertainment, and an antidote to the financial realities of the audience who saw it. And although their dialogue appears superficial, there is a subtle disconnect between what his protagonists say, and what they might really mean.

Amanda and Elyot are an utterly modern pair – as Coward and his leading lady, Gertrude Lawrence, were –the power couple of their own time (if not quite Posh'n'Becks). Like their real-life counterparts, Amanda and Elyot have all the toys of a new consumer era to hand. The telephone and telegram are tools of their trade, the social media of their age. If they lived now, the couple would be tweeting their adventures, and announcing their couplings and partings on Facebook. Status? "It's complicated".

The -isms and fads of contemporary life constitute their argot, the conduit of their frenetic discourse. They are young, monied, and carefree. They live in a newly liberated world. Indulgence, fantasy and decadence combine to create the modern, psychologically analysed self-image of a sleek, fashionable couple.

They look the part, and dress in the best: Savile Row tailoring, haute couture, Bond Street accessories. Pomaded, tanned, scented, they're as up to date as the next fashion, the latest mode. This is the age of the motor car (itself a sexual liberation which the young couples watching the play would recognise), and of international travel for those who could afford – as they surely can. Their appearance and behaviour reflects the advances of the time. Women's short skirts, cropped hair and revealing clothes echoed a greater female emancipation. Amanda, like other women of her class, would have been of the first generation encouraged – via Marie Stopes's ground-breaking, Married Love, the first sex self-help book – to control her own sex life. She is a flapper – grown up.

Cosmopolitan, transatlantic, suave, ironic, and somewhat metrosexual, Elyot is the consummate playboy, undefined by old Victorian values of hard work. What does he actually do? We never know. But he is the perfect consort for the sophisticated, mondaine, independent, headstrong, heartbreaking Amanda. This pair are stratospheres away from poor bluff Victor and boring Sybil. They recognise the Duke of Westminster's deluxe yacht in the harbour. They drink the latest cocktails. They are au fait with psychology, television, "cosmic atoms" and rejuvenating hormones.

Everything about Amanda and Elyot speaks of ever-accelerating change. They are role models, as were the playwright and his leading lady. In the 1920s "all sorts of men suddenly wanted to look like Noël Coward", wrote his would-be rival, Cecil Beaton, "– sleek and satiny, clipped and well groomed, with a cigarette, a telephone, or a cocktail at hand." Like Oscar Wilde, Coward commodified decadence for the masses. In Beaton's words, "It became a fad to talk with equal authority on specialised subjects as well as on frivolous ones... Noël Coward's influence spread even to the outposts of Rickmansworth and Poona. Hearty naval commanders or jolly colonels acquired the 'camp' manners of calling everything from Joan of Arc to Merlin 'lots of fun', and the adjective 'terribly' peppered every sentence."

Meanwhile, every woman longed for a bias-cut, silk-satin gown like Gertie's, a svelte figure, and sensational shoes. The theatre was increasingly reflecting that other modern medium (and rival), the cinema, and Private Lives was a lifestyle in itself, a series of intimate close-ups among immaculate set-dressing. It was Coward who was responsible for cocktail cabinets and cocktail manners even in the lowliest semi, where fantasies of Deauville, Dubonnet and balcony romances persisted, despite the reality outside. As in the movies, Coward gave people the chance to dream; to escape, as he had, the confines of suburbia for a brighter, Syrie Maugham-limed and chromium-plated world.

But does all this make them happy? Coward asks the question, but declines to answer. If his characters appear to be defined by their style, their facade is fatally undermined by that most quixotic and dangerous of all human failings: requited, passionate, unable-to-leave-one-another-alone love. Coward's lovers are never happy together, never happy apart. They shift and change with the fluidity of the times. They live in between two terrible wars, bookended by economic collapse, disaster, totalitarian politics, global threats. Little wonder that they live for the day. That chromium gleam has its darker side; what happens when the champagne runs out?

There's a sparseness, even a pessimism to their predicament – one much more redolent of contemporary drama. It would be easy to translate the plot of the play to modern Hollywood or a good British TV drama. Looking at them through a 21st- century lens, we recognise their fate. For all that they are portrayed – not least by themselves – as flighty, social creatures of a cynical age, their passions are intense, heartfelt, unplumbed. When the bedroom doors close, they suffer, like the rest of us.

Or rather, they suffer more, at the hands of their creator. For all his comic brilliance, Coward may have been one of the greatest tragedians of his time – one whose dark amusements still ring as clear as a chilled Martini today. That is the playwright's greatest achievement – to make us laugh so much we forget to cry.

'Private Lives', Gielgud Theatre, London W1 (0844 482 5130) to 21 September

Philip Hoare's 'Noël Coward: a Biography' is published by the University of Chicago Press