In March 2011 the head of a school in London asks one of her teachers, Khaled, who is from Libya, to give a presentation to students on the unfolding movement soon to be known as the Arab spring. No, he says, he’d rather not. He doesn’t “know much about politics”. The lie is transparent. As Khaled’s friend Hosam says to him, history is a “tide” and no one from their country can swim away from it. “We are in it and of it.”

Hisham Matar’s own life has been cruelly disrupted by that tide. His justly acclaimed work of nonfiction The Return described his father’s abduction by Gaddafi’s forces, his disappearance into the dictator’s prisons, and Matar’s decades-long quest to discover his fate. That book’s content was shocking, but its manner was quiet and tentative, all the more powerful for meeting brutality not with anger but with sadness.

This novel is equally delicate, intellectually and emotionally, and equally bold in its formal arrangement. Three young Libyan men, in exile in London, become friends, become estranged, come together again, part for ever. Their story reaches back into their childhoods, but the main narrative begins in 1984, the year that officials inside the Libyan embassy in London’s St James’s Square fired a machine gun into a crowd of unarmed protesters.

Two of the friends, Khaled and his fellow student Mustafa, are among those shot. For weeks they are in hospital, recovering from wounds in a ward guarded by police. The boys, students at Edinburgh University, know their absence from classes will be noted by the “wires”, Gaddafi’s spies in their cohort. They can never go home. To add to the pain of it, they cannot even tell their frantic parents – over tapped telephone lines – why they are staying indefinitely in their country of exile.

The third of their group, the slightly older Hosam, is a writer. One of his stories, a political allegory encouraging defiance of the Libyan regime, is read out over the BBC Arabic World Service. Shortly afterwards the newsreader responsible is murdered in the Regent’s Park mosque. That murder, like the embassy shooting, really happened. Matar is introducing his fictional characters into historical tableaux, thereby giving those public events the immediacy of personal experience.

The novel begins with its ending. Hosam and Khaled, now middle-aged, part as the former goes off to live in California, while Mustafa is in Libya with the militias. Khaled is the narrator. He sees Hosam on to a train at St Pancras, and then walks, by a circuitous route, all the way back to his flat in Shepherd’s Bush, reflecting and reminiscing as he goes. His view is retrospective but he has none of the arrogance of hindsight. “I don’t know why I did that,” he says. “I’m not sure what he meant by that.” “I still don’t understand.”

Matar’s narrative spirals, returning repeatedly to crucial moments, some almost silent. Gradually the reader works out – though it is unclear whether Khaled does – the reason Hosam stopped writing. We come to understand, although they don’t, that the three men are unable to form happy families because everything in their lives is provisional – to commit to love would be to commit to exile.

When the revolutionary moment comes to test them, they respond in unpredicted ways. Mustafa, the suave, sardonic estate agent, becomes a warrior. Hosam – so cosmopolitan, so self-contained – falls in love again with home and Arabic poetry and a female cousin. Khaled, the self-effacing schoolteacher, does what may be the bravest thing: accept the modest, useful life he has created for himself in London and resolve to be true to it. In a gently ironic nod to his own most famous book, Matar notes that Khaled may eventually visit his parents in Tripoli, but then he will “return” not to his idealised and traumatised birthplace, but to the place where he has become an adult.

The book is artfully paced. Long, mellifluous, meditative sentences are punctuated by short ones of bell-like clarity. The framing device of the cross-London walk is often submerged as the stories of the past overlay it. Time slows down for episodes of intense experience, then speeds up to allow marriages, births and deaths to flash by in a brief paragraph. Events in the immediate past of the novel open out into recollections of the deeper past: Hosam becomes obsessed with bygone instances of assassination of foreign visitors in London’s streets. All three friends are bookish. They talk about Conrad – a foreigner in England, as they are. The texture of the storytelling varies. It is intercut with dreams, with visions, with Hosam’s fiction, with a poem, with a visit to the National Gallery where Khaled contemplates a portrait by Hans Memling. (Matar has written about his own practice of regularly revisiting, for months on end, a single painting.)

This is a book about exile and violence and grief, but it is above all – as the title tells us – a study in friendship. Khaled loves his two friends, although he doesn’t always like them. He observes their rivalries. He is hurt when they exclude him. He is often self-deluded, but the frankness with which he thinks, as he walks and remembers, about what they have meant to him, gives this quietly spoken book a slow-growing but impressive force. “Friends,” says Hosam. “What a word. Most use it about those they hardly know. When it is a wondrous thing.”

• My Friends by Hisham Matar is published by Viking (£18.99). To support the Guardian and Observer buy your copy at guardianbookshop.com. Delivery charges may apply. From Friday 8 December 2023 to Wednesday 10 January 2024, 20p from every Guardian Bookshop order will support the Guardian and Observer’s charity appeal 2023.