Private Lives, Chichester Festival Theatre

“Has it ever occurred to you that flippancy might cover a very real embarrassment?" Elyot's response to fulminating Victor is a line of defence – and since he has run off with Victor's wife Amanda he has a good deal of defending to do. But the line is also Coward’s statement of intent. It's a direction as to how Private Lives works and is the key to why it’s not just his funniest and finest play but one of the greatest in the language.

The delicious flippancy is the (relatively) easy bit. For years, Coward revivals did little else. Well-dressed actors with good teeth (diction, darling), draped themselves over art deco furniture and spoke frightfully fast in a veddy, veddy brittle voices. And, indeed, the all-important look is in flawless hands here via the understated elegance of Anthony Ward’s design – his chic sets are in period (1930) while never yelling PERIOD and the cast shimmer in clothes beautifully cut for maximum flow. 

Private Lives is like the world’s most thrilling mixed doubles match

Smarter directors, Kent included, have lately been heeding Elyot’s line and upping the ante on the embarrassment. After all, brittle though it seems, this blissfully witty marital comedy of (deliriously bad) manners is about lovers on the edge of a nervous breakdown. 

Five years after the wreck of his tempestuous first marriage, Elyot (Toby Stephens) is dressed for dinner on the first night of his second honeymoon. He’s musing about his marriages on his Deauville hotel balcony when who should appear from the adjacent room but Amanda (Anna Chancellor), wife number one, on the brink of her own second honeymoon. 

So far, so symmetrical. But the amusingly formal structure helps ground and fire up real passion. Furious and not a little frightened by the other’s reappearance, they are seized with horror and mounting excitement as they realise they should never have divorced. Consequences be damned, they must flee. Right now. 

Those consequences are chiefly their distraught brand-new spouses Sibyl (Anna-Louise-Plowman, pictured above with Stephens) and Victor (Anthony Calf) who eventually catch up with them in Amanda’s Paris apartment. But by the time the injured parties turn up, the high comic passions between Elyot and Amanda have risen to a level of intoxication that’s near illegal.

That, at least, is the theory and whenever the mercurial Anna Chancellor is in control of Coward’s expert rallies – Private Lives is like the world’s most thrilling mixed doubles match – everything takes off. Not only does she have whiplash timing, she never anticipates a line so the audience hangs on her every word. She launches speculative lobs with epically droll assurance, and slices one-liners past her opponent leaving him (and the audience) gasping.

Positively glittering with wickedness, Chancellor achieves all this with a level of apparent physical and verbal ease that is frankly awe-inspiring. Unfortunately, Stephens (pictured left) doesn’t match it. Right at the very end, his descent into childish naughtiness at the spouses’ expense releases an easy glee which has been missing. Elsewhere, although his Elyot is a flâneur, affecting to value oh so very little, Stephens’s work is too effortful. He replaces relaxation with visible effort and rage which makes lines indistinct and kills several of the laughs. 

The lack of exhilarating collective rhythm isn't helped by Plowman's rather shrill Sibyl. Since her performance lacks charm, it’s hard to see why he married her. But if she’s an insufficient foil, the same cannot be said for Calf. Not the youngest of Victors, Calf turns that to advantage. He makes Victor solid (which is why Amanda marries him) but not stolid. And his final showdown with Amanda is free of pomposity and bluster that can sink the role. Calf allows us to see a man who, sadly, simply cannot understand the appalling recklessness around him.

Their all-too-brief scene is an oasis of calm, the production’s two finest actors plumbing the scene's depth but never overplaying it. They recognise that the emotions are an undercurrent. Elsewhere, as if missing the key point in Coward’s unspoken directive that flippancy should cover embarrassment, Kent’s revival is so busy uncovering the passions and turning sub-text into text that the surface sheen vanishes and tension evaporates. Coward's triumph was to write a play about emotional pain quite brilliantly disguised as a helplessly funny comedy. Showing off the pain diminishes the pleasure.

• Private Lives at Chichester Festival Theatre until 27 October