A few years ago I wanted to write about gay life in Algiers, where homosexuality is illegal and, if you’re not careful, can get you killed. There is, however, a busy, if well-hidden, gay underground in the city, as there is in most Arab countries. I found it relatively easy to make a few contacts, who all insisted that we meet in a “neutral” restaurant in the embassy district of Hydra, which is well guarded by government and foreign soldiers and a difficult place for hardline Islamists to penetrate. The watchwords for being gay in Algiers, I learned, were secrecy and discretion. There were no clubs or bars to go to, but rather invite-only private “parties”, along with the riskier, potentially lethal business of cruising the port area and main boulevards. Significantly, everyone I spoke to was upper-middle class, which ensured a certain immunity from suspicion and accusation, and they were diffident about their Islamic faith. To be working class and gay in Algiers, as well as a devout Muslim, is quite another matter.

Ludovic-Mohamed Zahed grew up in a working-class family in Algiers; from the earliest age he knew he was gay and had no idea what to do about it. It did not help that his father was a sometimes violent man – the very incarnation of “rajul”, the Algerian dialect word for a man and his machismo – who hated his son’s effeminacy. Zahed was also a pious Muslim, experiencing real spiritual feeling, which persists in him to this day. The first part of this book is a gripping description of living two realities at once: the life of a religious young man who is ever aware that his sexuality, as it develops, is anathema to his religion, his family, his friends and society at large. Zahed’s fears are deepened against the background of the civil war that took place in Algeria in the 1990s, when hundreds of thousand of people were killed and Islamist guerrillas massacred as many “miscreants” as they could, including homosexuals.

Zahed’s loneliness is crippling. The way out, if there is one, is to be found in Zahed’s friendships with his “brothers” in religion, whom he exalts for their beauty and nobility, even if they would despise and betray him, and even let him be murdered, if they really knew who he was. This sublimation of erotic feelings, and the ensuing tension between piety and eroticism, is not unique to Islam; in the Christian tradition, the Song of Songs and the Carmelite mystics are just two examples of this form of devotion. Zahed buries himself in scripture and, as many have done, finds that the Qur’an is in fact far less prescriptive about sexuality than is usually assumed.

Islamic scholars will debate this, but Zahed is convinced that the taboo against homosexuality in the Arab-Muslim world is mostly a cultural phenomenon rather than a religious edict. This is a comfort, and the second half of the book details his efforts to spread this good news to other gay Muslims through his own mosque in Paris, where he now lives, and through an organisation called HM2F (Homosexuel(le)s Musulman(e)s de France), which he founded in 2010 to provide a haven for LGBTQ+ people.

Significantly, Zahed’s salvation comes in France, a secular and impious country, but he remains viscerally attached to Algeria, where his sexual desires and political activity would be impossible. This is compounded by the fact that he grew up with Salafism, which has become the predominant form of Islam in working-class Algeria. Salafism is a puritanical, hardcore import to north Africa, where the traditional school of prayer is Malikism, a fairly tolerant branch of Islam that allows for music, magic, folklore, superstition, women’s rights and a fluidity towards sexual matters. Accordingly, Zahed is able to argue that the welcoming version of Islam he espouses belongs to an older north Africa and that a return to these values should be the way forward.

He knows, too, that this argument is doomed in an Algeria where, in the past few decades, class differences have been marked out by an aggressive Salafism, which promotes hatred of the moneyed elites who rule the country. The bourgeois gays I interviewed in Hydra were the sons and daughters of these elites, and had little or nothing in common with Zahed and those of his class. Still less does their “decadent” lifestyle have any appeal for Zahed, who sees his life as a spiritual pilgrimage.

This is a sad book. Zahed wants to spread hope but this is less a convincing polemic than a melancholy memoir written in double exile – literally, since Zahed has had to make France his home, and also because he remains divorced from the “brothers” who fostered and nurtured his faith when he was growing up.

Zahed’s is a moving, courageous voice, but he also acknowledges the isolation of his position in an Islamic world where attitudes to sexuality have only hardened in recent years. But it is for this very reason that Muslims and others alike need to listen to him.

Andrew Hussey is professor of cultural history at the School of Advanced Study, University of London, and the author of The French Intifada: The Long War Between France and Its Arabs (Granta)

• The Koran and the Flesh: The Pilgrimage of a Gay Imam by Ludovic-Mohamed Zahed is published by Swift Press (£16.99). To support the Guardian and Observer order your copy at guardianbookshop.com. The French Intifada: The Long War Between France and Its Arabs order your copy at guardianbookshop.com