The vision that greets you on entering the Royal Academy’s new sculpture exhibition, Wild Thing, is Eric Gill’s sister, Gladys, making love to her husband, Ernest Laughton. No reproduction can do justice to the elemental honesty and pulsating energy of this Portland stone sculpture, Ecstasy, carved by Gill in 1910, nor prepare you for the animal passion of its eroticism. With elegant economy Gill describes the tensed curve of her back, her single erect nipple, the straining muscles of the two lovers and the creamy acreage of buttock and thigh. Mellifluous linear rhythms flood the folds and escarpments of these two bodies, locked together on the brink of ecstasy.

In his diaries, Gill referred casually to the work as “the (big) group f***ing”. Massively daring for its time, its display was out of the question for Gill’s first solo exhibition in 1911 in the Chenil Gallery in Chelsea, but the work was bought by Edward Warren, the wealthy English collector who had commissioned Rodin’s monumental marble The Kiss in 1904. Judged simply on the appearance of its passions, Ecstasy was wildly more outrageous than Edwardian society could ever accept. But a far greater scandal would have erupted had the public known that at the time he was working on this piece, and others like it, scrutinising his sister and brother-in-law making love, Gill was embarking on the incestuous relationship with Gladys that was to last most of his adult life.

Only when you have torn your eyes from this masterpiece do you register the extent of the treasures in this first gallery, entirely devoted to the work of Gill. Ranged around the walls are hunks of Portland and other pale stones that have been fashioned with impossible refinement into human figures engaged in the elemental business of life, death and reproduction. Wandering around the room, fighting the urge to touch, you are struck afresh by the gravity of the nude human body, and by the honesty of Gill’s gaze.

Gill’s is just one of three galleries in this exhibition, curated by Richard Cork and Adrian Locke, the other two being devoted to the work of Henri Gaudier-Brzeska and Jacob Epstein. Together they tell the story of how these three young and subversively daring artists revolutionised their field of sculpture in a sustained burst of activity during the run-up to the First World War.

The three men came from wildly disparate backgrounds but found their circles overlapping in London. Gill was one of 13 children of a Brighton clergyman, Epstein was a Jewish immigrant who had arrived in London in 1905 from New York via Paris, and Gaudier-Brzeska was the son of a joiner from Orleans. Epstein provides the link between the three. For years, he was a close collaborator with Gill until the pair fell out over a shared plan to create a new religion. After this friendship waned, Epstein met the precocious GaudierBrzeska, 11 years his junior, and took him under his wing, encouraging and nurturing his ideas and supporting him in his work.

All three artists appeared in London at a time of febrile change, a period, as Cork writes in his catalogue, in which “a spirit of fanaticism invaded a luxurious world which no longer felt itself secure”. They worked with ferocious energy and intensity at a particular time in the history of British sculpture, introducing a kind of rude elemental force into their field, which celebrated erotic delight, virility, birth and mortality, and expressed the great primal facts of man and woman. All three of them revelled in challenging and upsetting conventional expectations.

Their work drew on continental inspiration from Brancusi, from Modigliani and, in Gaudier-Brzeska’s case, from Alexander Archipenko, the Russian cubist sculptor, all of whom were working on pure human features, shorn of detail, which became symbols of a state of mind. In other spheres too, such as painting, a new wave of heresy was attacking the academic pillars of art, with challenging works by Gauguin, Cézanne and Van Gogh being shown in London for the first time.

In their fearlessly subversive approach and in their abandonment of modelling in favour of producing works cut straight into the stone, “conceived and born in stone”, they were hugely influential on the course of early 20th-century sculpture in Britain. We can see it at almost every turn in Gill’s gallery. One of the major works shown here is the pair of stone reliefs made in 1910, Crucifixion and A Roland for an Oliver. The former shows a puny figure of Christ on the Cross, his legs as thin and helpless as a child’s, his genitals minuscule, his chest frail. Next to this is the boldly sensual depiction of a naked woman in A Roland for an Oliver (according to Gill’s brother, this meant “tit for tat”).

She stands strongly with her powerful legs wide apart, her hands thrusting provocatively down from her hips. Her genitals are unashamedly on display, her full breasts as round and plump as a pair of boxing gloves. Her hair blows in the wind and on her face is a smile of lascivious pleasure. With his rebellious sense of humour, Gill could not resist this provocative pairing: on the one hand showing the power of sacrificial love shrinking male bodily strength into insignificance, on the other showing the frank power of female sexuality. It would no doubt have caused extreme offence to Roman Catholic priests, who believed, according to one contemporary observer, that sex was “like being in the WC (quite pleasant, not necessarily sinful, but only a dirty function)”.

Gill was a man of diverse accomplishments. Trained as an architect, he had mastered lettering techniques and masonry. He could draw from life, produce anatomical drawings, design reliefs and perform monumental works of stone carving. He had demolished the distinction between fine and applied art. He worked like a demon, chiselling, drawing, designing, painting, all the while trying to reconcile his untrammelled sexual appetites with his religious faith.

The works here are mainly stone carvings, although there are some drawings and a small number of examples of his lettering. His figures are delightfully vigorous and highly sophisticated. There are naked boys wrestling, there are various versions of Christ on the Cross, and there are peaceful depictions of mothers breast-feeding their babies, some chiselled and smooth all over, others allowing the creamy stone to give way to a rough unpolished surface, the contours crumbling softly like dunes so that a world of suggestion is conjured from the rubbing of surfaces.

Gaudier-Brzeska was no less bold in his treatment of humanity. He arrived in London in 1912 with his Polish-born companion Sophie, who was 20 years his senior and who only agreed to live with him on condition that they avoided sex. Sophie acted as his surrogate mother, leaving the intensely excitable and hungry-faced artist to vent his energies in his work.

Having visited and been greatly impressed by Epstein’s studio as a young arrival in London, he drew and modelled feverishly, producing early in 1912 an extraordinarily powerful figure in lead of a wrestler, which we see here, as well as female nudes in alabaster and stone, and a beautiful small carved figure lying on a tile of white marble entitled Mermaid. Growing organically out of the surface of the block, this soft sinuous figure lies in one corner, her hair and tail emerging from what might be a milky white sea. Chipping and chiselling, carving direct from the stone, Gaudier-Brzeska had removed everything from this block of marble that was not the mermaid. In this way he had taken on Gill’s and Epstein’s passionate belief in “carving direct”, a belief in the importance of conceiving things and allowing them to exist in stone, letting the shapes emerge from the stone from which they came.

Gaudier-Brzeska was said to have “talked like a chisel and argued like a hammer”, and some of his works, such as Bird Swallowing a Fish, have a distinct sense of brutality. In 1914 he created a monumental head of his friend Ezra Pound out of a vast metre-high block of marble. Influenced by Polynesian sculptures that GaudierBrzeska had seen and studied in the British Museum, the figure is a monolithic tour de force, a huge hunk of titanic energy, that glowers with barely contained power.

If the young Gaudier-Brzeska was daring, Epstein, represented in the final room, was more fearless still. Having seen the smooth voluptuousness of Gill’s figures and the Vorticist expressions of Gaudier-Brzeska’s, some of Epstein’s ideas take your breath away for their sheer audacity.

In 1908 Epstein had triggered a national scandal with his series of nude male and female sculptures carved for the upper floor niches on the British Medical Association building in the Strand. Situated directly opposite the notoriously censorious National Vigilance Association, the works were condemned by the Church, the public and the press until a group of artists (including Gill), critics and museum directors came to his aid with support. A charming pencil and ink drawing for one of the figures is in this show, displaying the frankly sexual, rounded forms of a pregnant woman, one of the key figures that had caused so much of the upset. Unabashed, Epstein continued to rescue British sculpture from, as Gill argued, “the grave to which ignorance and indifference had consigned it”.

In 1913 he created a towering marble figure, Venus, a multilayered work that celebrated the powers of procreation and showcased Epstein’s new interest in dehumanising the human figure. A robotic female form perches perilously above two mating doves, her breasts hanging like long pendulous handles, her face reduced to a blank angular mask. And then in 1913 he conceived his most revolutionary work of all, Rock Drill, in which he confronted technological progress and its dehumanising force, and presaged the massive destruction about to be unleashed across Europe.

With his masked robot balancing on top of a massive piece of machinery, a real rock drill tripod, Epstein did his best to revolutionise 20th-century sculpture. If you look at the work that was to come later — of Henry Moore, of Elizabeth Frink and of Antony Gormley — the influence of Rock Drill, and of many more of the works in this show, is manifestly clear.

Wild Thing: Epstein, Gaudier-Brzeska, Gill is at the Royal Academy, W1 (www. royalacademy.org.uk), from Sat to Jan 24

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