First, a confession. I used to preface writing about musicals of the post-Sondheim/Bernstein era with the excuse that they were a break from the more intellectually demanding role of reviewing “serious” plays. Now I am very happy to include musicals in the regular core business of a critic. A resurgence of musical theatre showcasing intelligent work on both sides of the Atlantic is the reason. Hamilton premiered in 2015 with a libretto that could deal with the strains of the American constitution and the persistent philosophical tensions of forging e pluribus unum across the vast United States. Bartlett Sher decolonised The King and I in 2018, challenging its dusty stereotypes but maintaining its haunting beauty. He brings his fresh gaze to My Fair Lady with a feminist twist in London this year.

At the grittier end of the musicals spectrum is Steven Levenson’s Dear Evan Hansen, which just opened at London’s Noël Coward theatre. I could have told you it would be a hit before it reached these shores, having heard it blaring out from my teenage daughter’s bedroom soon after its Broadway premiere in 2016. Michael Greif, a Broadway veteran, directs the story of the anxiety-ridden adolescent embroiled in a dystopia of lies, insecurities and the teenage feat of finding no way out of the mess you have made.

Like all the most durable stories, this plot about the intrigues of young millennials is rich in echoes of far older works. At heart it is about the propensity of human beings to lie, while at the same time expecting others to tell the truth.

So — as the millennials would say — our perspiring hero Evan (Sam Tutty) is a high-school senior who suffers from anxiety of the leg-twitching, hand-sweating type, a curse not only familiar to teenagers. He talks himself into trouble, blurts out the wrong thing and then can’t stop apologising. All of this is a dead-cert recipe for being an outcast at school, where he has a passing acquaintance with his depressive, dope-addled classmate Connor Murphy, on the grounds, as Connor observes, that “now we can both pretend we have friends”.

At 21 Tutty is a newcomer to the West End and nails the part as an ardent, people-pleaser living with his harassed single mum (Rebecca McKinnis), struggling with the role of sole emotional sustainer and strained finances. Everything grown-ups do in the story makes things worse (echoes of the incompetent families in Romeo and Juliet). Urged by his mother and therapist to write upbeat letters to himself, poor Evan finds his first halting attempt at self-encouragement snatched by petulant Connor. Shortly afterwards, Connor kills himself, leaving the grieving parents assuming the note they find in his pocket is written to Evan Hansen.

The convolution of the plot and mistaken identity of letter writers owes a lot to a longer tradition of comedy: the power of the written word, in the wrong hands, to engineer chaos and misunderstanding. The deception is really a springboard for touchy social topics — from teenage suicide and its aftermath, to depression and the gruelling echo-chamber and Salem of social media. Levenson created Hansen in his late twenties, a reminder that we are now in a generation of theatre writers who grew up in the world of Facebook and Instagram.

As in molière’s Tartuffe or Patricia Highsmith’s The Talented Mr Ripley, the driving suspense turns on the inevitability of discovery. Duly the fates arrive in the form of the vector of social media, when Evan’s emails, fabricated in collusion with a more cynical friend, turn the original deceit into cultish memorialising of the dead boy.

It’s worth pausing on why Evan Hansen feels secure in territory that could have turned mawkish. The Politician on Netflix, for example, enters into the same territory of young suicidality and the dislocation of experience and self-image. Not even a star cast, however, could hide the hole in its too-clever-by-half heart. The moral point Dear Evan Hansen makes with a light touch is that those keenest to be duped are credulous for their own reasons.

The online hubbub of the “Connor Project” might well have figures in the “the great stage of fools”, as Wycherley observes in his late-seventeenth-century intrigue The Country Wife. Initially, Evan cannot bear to disappoint the Murphys (Lauren Ward and Rupert Young) when they adopt him as a surrogate son.

Yet he also gains a conventional family, the acceptance of his peers and a love-interest in Connor’s sister Zoe (Lucy Anderson) in the process.

A fair criticism is that it has only one punchy showstopper, “Sincerely me”, jauntily capturing the essence of the twisting tale. But then no one can remember a single tune from Billy Elliot, probably not even Elton John, who wrote it. The music here comes from Benj Pasek and Justin Paul (who co-wrote the music for La La Land and the mood is similarly bitter-sweet). There is a searing lament from Zoe for a brother she senses is being misremembered: “I will sing no requiem tonight.”

Evan’s pretence finally falls apart, crowned by an ending that suggests the bad stuff will turn out all right in the end if you come clean, leave the echo-chamber and grow up a bit. A digital-savvy, tech-addled new generation has found its voice in a deceptively accomplished musical.