You Write The Reviews: If Hitler Had Been A Hippy How Happy Would He Be, White Cube Mason's Yard, London

This exhibition of work by Jake and Dinos Chapman is by far the most impressive art show in town at the moment.

On the ground floor of the White Cube gallery in Mason's Yard in St James's there are 17 portraits in oil of individuals with grotesque facial defects, all entitled, One Day You Will No Longer Be Loved. In the basement are 13 original watercolours by Adolf Hitler that the Chapman brothers have prettified, mainly by adding concentric rainbows in garish colours. But the centrepiece is an enlarged reconstruction of their unforgettable work Hell, exhibited in the Royal Academy in 2000 and destroyed in a warehouse fire in 2004.

Fucking Hell, as it is now called, consists of nine vitrines with tiny glass-fibre and plastic figures participating in scenes of torture and slaughter on a monstrous scale. The variations on the theme of human evil seem endless. Everywhere there are soldiers, skeletons, skulls, body parts, vultures, tanks. A skeleton figure totters on the gun barrel of a tank and uses a balancing pole with a skull impaled on either end. At one corner of a killing field covered several metres deep with corpses, Hitler surveys the carnage and paints instead a blissful landscape of the type on view in the next room of the gallery. In Anne Frank's house, someone is sewing a garment from body parts. On a dystopic tropical island, the cosmologist Stephen Hawking sits on a miniature tank, while luridly coloured vultures are perched in the trees and tourists with limb deformities frolic on the beach. One vitrine contains a death camp. There are several swastikas formed from amputated legs.

The torture and killing seem to encompass the whole universe. Many of the humans are genetically deformed. Animals are not spared: a pig is crucified, sharks have swastikas on their fins. Some trees have no leaves but their branches sprout human heads. A huge rock formation takes on the shape of the mushroom cloud of a nuclear bomb. Not even history is excluded: the pediment of a Greek temple depicts broken bodies instead of gods and heroes.

The Chapman brothers have created a harrowing masterpiece of uncompromising bleakness, which is surely meant both to disturb us and to motivate us to action. "What are we doing about Darfur or Zimbabwe?" is one of the urgent questions that this fierce and incandescent work of art suggests.

Paul Crichton, consultant psychiatrist, London