Here is a strange sight to find in the heart of cynical old London, just a stone’s throw from the Square Mile’s glinting temples of Mammon. On the walls of Flowers East, one of Shoreditch’s trendiest art galleries, are 14 Stations of the Cross: literal depiction's of Christ’s trial, Crucifixion, death and burial. They are the sort of things one usually encounters in ancient Italian churches — faded souvenirs from an age when religious faith was the most powerful force in life and society, and the Church all-powerful.

But today? in cheerfully profane and materialist Britain? On a Good Friday that will see far more people snapping up bargain begonias in garden centres than on their knees in church? These images seem so out of step with the Zeitgeist of modern art galleries, modem cities, modem life, that one wonders whether they are 15th-century icons, dusted off by some clever-clogs curator for “ironic” Postmodern effect.

Nothing could be further from the truth. The Stations of the Cross are the latest works from the tempestuous imagination, tortured soul and vivid brush of the Scottish painter Peter Howson. And there is nothing remotely ironic about them. They depict — up close, and in such graphic detail that you can practically smell the fear and sweat — the face of a ravaged Christ: the veins swollen in agony, the bulging eyeballs staring feverishly, the blood and grime matted around the crown of thorns, the pallid flesh horribly blotched.

You wonder where you have seen this prematurely aged face before, and the truth is disquieting when it comes. It is the face of the beggar scrabbling in the bins on Moss Side’s streets. It is the meths drinker shrouded in a filthy blanket underneath Waterloo Bridge. It is the junkie who overdosed and died a squalid, lonely death in the stairwell of a Hackney estate.

Painted with virtuoso control on tiny squares of oak, the Stations themselves are too small to focus on anything except Christ himself and, occasionally, the grieving Mary. But the exhibition also includes sketches that flesh out the surrounding scene. These, too, accentuate the disturbing feeling that this Christ is being crucified here and now, right before our callous or indifferent eyes.

Nothing new about that, of course. Stanley Spencer’s 1920 classic, Christ Carrying The Cross, relocated the Via Dolorosa to Cookham High Street — replete with gawping locals— much to the irritation of residents of that charming Berkshire village. But Spencer’s art was an altogether more genteel affair. Howson’s paintings, by contrast, exude brutality — and it is recognisably the brutality of our own age. The nails are being hammered into Christ’s wrists by modem construction workers. The “Roman soldiers” look suspiciously like the military thugs depicted in the terrifying images that Howson painted after his two stints as The Times war artist in Bosnia, In his hands, suddenly, the Crucifixion story doesn’t seem so irrelevant after all.

Even so, it is a brave subject for a top British painter to tackle. Avant-garde artists are supposed to do pickled sharks, discarded condoms and elephant dung, not Christianity. Not in this country anyway. It’s passed. It doesn’t sell. The “buzz” is elsewhere. Howson was lucky enough to find a rich American Catholic who commissioned Stations of the Cross and will eventually install them in his chapel. But the artist publicly complained that no gallery in his native Scotland was willing to exhibit them, such was the art world’s hostility towards his faith. “Religious art is the kiss of death,” one gallery owner said, with presumably unconscious irony.

Is this true? It’s certainly the case that, for most of us, the phrase “religious art” evokes something created centuries ago — like the Bach Passions that will today transport thousands of music lovers, even sceptics and agnostics, temporarily into a world of 18th-century Lutheran fervour and certainty.

Yet my impression is that the Crucifixion retains a colossal power to inspire contemporary artists, writers and musicians — almost, in some cases, in spite of themselves. I think only of the extraordinary projects and performances I have seen in the past decade. Two of the finest living British composers, Jonathan Harvey and James MacMillan, have produced epic operatic and orchestral works about Christ’s Passion and Resurrection, each fierce, fervent and compelling. But they come from Christian backgrounds. More astonishing, perhaps, is the case of Tan Dun, the Chinese composer (best known for his Os­car-winning soundtrack to Crouching Tiger, Hidden Dragon), who wrote a remarkable 250th-anniversary homage to Bach, and to Bach’s unshakeable Christian faith, called Water Passion after St Matthew.

Tan is a Buddhist, brought up in a remote Chinese province. He didn’t hear a note of Bach (or read a word of the Bible) until he was in his twenties. Yet the drama and symbolism of Good Friday struck a chord with him. As a teenager he had been forced to work for two years in the rice fields as a punishment for “dangerous intellectual habits”. For him, he said, the Crucifixion unlocked “images of torment, humiliation and the arbitrariness of power during the Cultural Revolution”. In that respect, his Water Passion recalls Sir Michael Tippett’s wartime oratorio A Child of Our Time, which mirrors Handel’s Messiah but transforms the story of Christ the scapegoat into a contemporary tragedy of a Jewish boy persecuted by the Nazis.

Modern poets, too, have devised striking reinterpretations of the Crucifixion. No one can pretend that the great flood of English-language Christian verse that extended from Donne and Milton to T. S. Eliot has not dried to a trickle. Even so, when the EEC commissioned a series of new Holy Week poems a few years ago they found no shortage of willing authors: James Fenton evoking the intolerant Jerusalem of then and now; Roger McGough wryly putting himself in the shoes of Judas Iscariot’s father, and imagining the frustrated fury of those who expected Christ to instigate “regime change” in Judaea; and so on.

Even weightier were the ‘sacred conversations” written two years ago by Andrew Motion, the Poet Laureate, to be read between the movements of Haydn’s “Good Friday” string quartet, The Seven Last Words of Our Saviour on the Cross. Cast as dialogues between a self-obsessed poet (presumably Motion himself) and a ghostlike figure who is sometimes Christ, sometimes the poet’s dead brother, and sometimes the still small voice of conscience echoing faintly through 2,000 years of bloodstained “Christian” crusades and sectarian conflicts, these encounters gradually reveal to the poet (Everyman, if you like) his social, moral and spiritual obligations. Motion’s message, in the end, is that materialism, hedonism, consumerism, egotism — and all the other soul-stifling “isms” of modem life —are not nearly enough.

For any poet, artist or musician to promote that view in present-day secular Britain is a bold act, inviting incomprehension, hostility or scorn. But then, the most profound Good Friday and Easter art has often been produced in defiance of oppressive social or psychological pressures. Think of Heinrich Schutzz, writing the first great Lutheran passion music — compositions of unwavering assurance and sublime beauty — while the Thirty Years’ War reduced all around him to ruins. Or of Mahler, transcending the desolation of a childhood scarred by death and grinding poverty to write his Resurrection Symphony, one of Western art’s most exultant proclamations of the soul’s immortality.

Howson, I think, also has this transcendental capacity, which is why his Stations of the Cross have such scary power. God knows, he has been hauled through life’s mangle a few times, and he’s not yet 50. Afflicted with Asperger’s syndrome, he has survived severe cocaine addiction, a period when he was drinking two bottles of vodka a day, two marriage bust-ups and a mental breakdown after his Bosnian experiences.

Not surprisingly, perhaps, the Christ he depicts is not the King of Glory portrayed in the triumphalist stained-glass windows of mighty cathedrals, but a companion in suffering — “despised, rejected; a man of sorrows, and acquainted with grief’. Perhaps it takes one to know one.

Either way, his Stations shatter the fashionable notion that Christianity is an exhausted philosophy, fit only for the feeble-minded and the terminally complacent. Nothing in a London gallery this year (and particularly not the extravaganza of inconsequential Britart piffle put on by Charles Saatchi at County Hall) is likely to be more genuinely provocative than the wild, terrified stare of Howson’s Christ: the face of out­casts everywhere, and for all time.

Richard Monison