Richard Cork looks at a young artist's response to the horrors of the Spanish Civil War

Appalled by the internecine savagery fracturing his native country, Picasso produced a violent and eruptive denunciation of the conflict. Guernica, which takes as its springboard General Franco's barbaric bombing of the defenceless Basque capital, became the definitive Spanish Civil War painting from the moment it was installed in Spain's Republican Pavilion as part of the Paris Exposition Internationale. Unveiled in June 1937, Guernica has overshadowed every other attempt by anti-Fascist artists to make images exploring the Spanish tragedy. But they do not deserve to be neglected, and Tate Members' recent acquisition of Andr Fougeron's little-known painting throws welcome light on another forceful and impassioned attempt to arraign the evils afflicting Spain and its beleaguered people.

Although much simpler than Picasso's frieze-like tour de force, Fougeron's canvas achieves a monumental power of its own. Inscriptions on the back of the canvas reveal that he worked on it, intermittently, from January until June 1937. So he may well have executed the final revisions after seeing Guernica and being overwhelmed by its colossal, headlong attack. Fougeron's decision to concentrate on a woman and horse certainly chimes with the subject matter chosen by Picasso, but the women in Guernica are alive. They fill the painting with frantic gestures and desperate, howling indignation.

Fougeron's painting, by contrast, presents us with the aftermath of a civil war killing. The body of a felled horse extends from one side of the canvas to the other, and nothing encourages us to imagine that the animal will ever emerge from its hunched stillness. The finality of death is beyond question, even if the horse's mane unfurls in a sequence of strangely feverish rhythms. Both its visible legs have buckled under unbearable pressure, and lie uselessly beneath the body's bulk. The tail may still explode in a tangle of wild tresses against the sky, but the animal's head already seems afflicted with rigor mortis. And the ominous whiteness spreading across its head has the aura of putrefaction, suggesting that the horse has already begun to fester and decay in the heat of the Spanish sun.

Fougeron's unequivocal emphasis on death implies that he felt more pessimistic about the Civil War's outcome than Picasso. Guernica's women and animals are undoubtedly in extremis, but they are still animated by a fierce dynamism. Martyred Spain, on the other hand, lives up to its title by insisting on extinction. The face of the woman who sprawls in the horse's shadow is hidden from view. We are obliged to imagine her twisted, and possibly beaten features, for her brutally wrenched-apart legs indicate that the woman has been raped. Malaria yellow, the limbs thrust out towards us with bony insistence. They could equally well belong to a pestilential body in a morgue, and her out-flung right hand terminates in fingers contorted with an intolerable degree of pain. The woman clearly suffered a great deal before dying, and Fougeron is in no mood to minimise the extent of her ordeal. He ensures that the horse's hoof guides our eyes inexorably towards her vagina, covering it and yet at the same time drawing attention to the vulnerability of her exposed sex. She has been abused by Fascists, who, not content with slaughtering Republican soldiers, amuse themselves by violating civilians as well.

Fougeron was only 25 when he executed this uncompromising picture. It can be counted among his first substantial achievements, and his precocity becomes more remarkable when we remember he had no formal training as an artist. A student of political science, he threw himself into painting with a zeal fortified by his commitment to Socialist Realism. Martyred Spain was intended as a political statement, and nobody who encountered it in the 1937 Salon des Surindpendants in Paris would have misinterpreted its polemic.

But it amounts to more than anti-Fascist propaganda. Despite the youthful enthusiasm of Fougeron's alignment with the International Communist Party, he reserves the right to handle this painting with considerable formal audacity. Not for him the clichd philistinism promoted by Stalin's cultural apparatchiks.

Fougeron indulges in ferocious distortion, startling viewpoints and brazen anatomical frankness. He is, at this early stage in his career, far closer to the temerity of Picasso than the wearisome painters who reduced officially sanctioned Soviet art to such a nullity during this period. Fougeron wanted his viewers to be incensed by Franco's callousness, but he also made them feel the violation in their own bodies as they confronted Martyred Spain and experienced the full, visceral impact of his unfettered painting.

Martyred Spain was purchased for the Collection by Tate Members.