According to a famous poem by Philip Larkin, “sexual intercourse began in 1963.” It hardly seems accidental that “On Chesil Beach,” director Dominic Cooke’s new film, like the Ian McEwan novel on which it’s based, takes place mostly in the previous year.

Florence Ponting and Edward Mayhew, young British newlyweds working up the nerve to consummate their marriage in a seaside hotel, are both virgins. But the problems they face owe less to their inexperience than to the absence of a shared vocabulary adequate to their feelings and desires.

Larkin, after all, didn’t mean that nobody went to bed before his designated “Annus Mirabilis” (the title of his poem). He meant that nobody talked much about what went on there, because they were in thrall to “a shame that started at sixteen/and spread to everything.” In the decades since, it can seem as if nobody has talked about anything else.

McEwan, the author, who was born in 1948 — and is thus a crucial decade younger than Florence and Edward (and a full generation younger than poor Philip Larkin) — has made a career out of exploring the gray areas between erotic innocence and carnal knowledge. In book form, “On Chesil Beach” has a gently retrospective point of view, with occasional sentences that foreshadow the enormous changes to come “later in that famous decade.”

The film, for which McEwan wrote the screenplay, draws a pictorial veil between past and present. As is customary with literary adaptations of this kind, subjective impressions are filtered through physical details. The production and costume designs (by Suzie Davies and Keith Madden) are impeccable and understated. You notice, and appreciate, the accurate rendering of the clothes the characters wear, the books they read, the food they eat and the bicycles they ride. The real 1962 could not possibly have felt this much like 1962.

This makes Florence and Edward’s world both beautiful and distant. The job of bringing it nearer and adding a human dimension to the beauty falls to Saoirse Ronan and Billy Howle, who are more than up to the task. Ronan may be the keenest, subtlest, smartest actress under 30 working in movies today, and while Howle’s is a less familiar face, it is one of those faces you can’t stop observing. He has some of the half-rough, half-pretty charisma of a young Michael York, and he plays Edward with a perfect blend of diffidence and defensiveness.

Edward and Florence, who encounter each other at a disarmament meeting on the Oxford University campus, court each other across a small but not inconsequential class divide. She is the daughter of a factory owner (Samuel West) and a philosophy professor (Emily Watson). Edward’s father (Adrian Scarborough) is a schoolmaster. His mother (Anne-Marie Duff), who suffered a head injury when Edward was a child, paints and makes collages and wanders around the house and garden in a state of permanent confusion.

Florence is a classical violinist, one of the founders of an ambitious string quartet. Edward, a graduate of the University of London, prefers rhythm and blues and dreams of writing a series of popular history books. Their interests and sensibilities, while not identical, seem perfectly complementary. They imagine a life ahead full of interesting conversations about politics, art and ideas, punctuated with leisurely picnics and walks in the woods. Their intimacy seems perfect, and their love is surely built to last.

Except for the sex part. “On Chesil Beach” has both a rich sense of how much more there is to life than sex, and also an acute awareness of how sex can overwhelm everything else. There is comedy in the shy clumsiness of the young couple, and also excruciating suspense as they make their way toward the hotel bed. What happens there is something perfectly ordinary — or at least entirely believable — and also cataclysmic.

Edward and Florence are creatures of their time, but McEwan and Cooke don’t insist on their representative status. Their story is highly particular, rooted in the idiosyncrasies of their families and also in an almost invisible crime, a tendril of evil that wraps itself around their destinies. The gentle surface of the film camouflages heartbreak and horror. Its lesson calls to mind another Larkin poem, which begins with a frequently quoted line about the damage done to children by their parents.

On screen, “On Chesil Beach” loses some intensity at the end, as the supple suggestiveness of McEwan’s prose is replaced by the stagy literalness of film. Perhaps this couldn’t be avoided. His novels are amenable to adaptation, but almost always lose a lot in translation. “Enduring Love” and “Atonement” are two recent examples.

“On Chesil Beach” is better than either of those. It’s a good movie. The book is something more — close to perfect, I would say — but since both incarnations emphasize the importance of tolerating human fallibility, I won’t make too much of the discrepancy.

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