Percy Wyndham Lewis (1882-1957) was one of the great literary, cultural and artistic polymaths of the 20th century. In addition to his huge contribution to the visual arts - he was a painter, draughtsman and printmaker - he wrote a tonnage of fiction, poetry and cultural criticism, from novels such as The Apes of God (1930), which mercilessly satirised his effete contem poraries (not least those pseudo-revolutionary members of the Bloomsbury set), to brilliantly ruthless appraisals of the painters and sculptors of his time. As the driving force behind vorticism, one of the few English avant-garde art movements of the pre-First World War period, he also had a considerable impact on the development of visual arts during the 20th century.
Yet, paradoxically, there has never until now been a comprehensive show of the many portraits he painted during his lifetime. A new show at the National Portrait Gallery in London - which consists of self-portraits, portraits of his great literary friends and contemporaries (more contemporaries than friends, in some cases) Ezra Pound, T S Eliot, James Joyce and Edith Sitwell, and portraits of his wife, Gladys Hoskins - adds up to a picture as rich, paradoxical and self-contradictory as any top-notch New York analyst might ever wish for.
At the heart of this show is a fundamental, no-holds-barred, lifelong contradiction between head and heart. We sense it the very moment we clap eyes on The Tyro, a savage and almost self-satirising act of self-portraiture that he completed in 1921, and which faces us as we prepare to enter the show proper. It throws itself down as a kind of challenge to any presuppositions we might have about Lewis the man. It serves as a warning, if you like, not to draw your conclusions too readily or too easily. The gruel that constitutes this man is exceedingly thick.
The portrait itself looks simultaneously ghoulishly mechanised and rompingly jokey. It is full of a kind of heartless mockery - of the world at large, and of the man who seems to be hazarding a guess at just one aspect of his own, multifarious identity.
Then, when we step into the first room, which is full of other portraits of Lewis by himself, he seems to become entirely different people - in fact, an entire cast of characters. In one late painting, we see Lewis as the suave, literary lounge lizard; in another, in one of those full-brimmed hats he used to wear, he looks every inch the traditionalist. What he never loses, no matter how many times he chooses to portray himself, is a kind of ruthless and suspicious watchfulness. It was as if Lewis himself didn't know who he was, so he had to be perpetually on the watch for the next Lewis who might emerge. Would it be like the last one?
W H Auden once called Lewis "that lonely old volcano of the right", and it is true that he not only showed sympathy for fascism and wrote books in support of Hitler (whom he called "a man of peace"), but also supported appeasement before the Second World War. All this reckless political posturing did his reputation much damage. Artistically, he gradually shifted from the severe abstraction of vorticism to something quite close to naturalism - as you can see in many of these portraits. Like his great forebear Jonathan Swift, he was ferociously vituperative, a sparkling polemicist from first to last, a great quarreller, a great maker of enemies. It is almost as if he lived to fight. What is more, he wrote at his best when he was at his harshest and most cruel. It was as if he was energised by the malign delight that he took in slowly flaying friends or enemies, it scarcely seemed to matter which.
Lewis was brilliantly cruel, in print, to most of the people whose portraits hang in these rooms. He hated Virginia Woolf and all that she represented - we see that in the way he has chosen to draw her here. Her face looks simian and rubbery; her hands are huge, clumsy, ill-placed, almost out of control.
And yet, in many of these portraits, there is a huge degree of sympathy for, and understanding of, the sitter. Consider his great portrait of Eliot, which the Royal Academy had the folly to reject in 1938. The fact is that Lewis has seen through to the man behind the mask of the sleek and suave cultural diplomat. He sees how precarious that mask is, and at what expense to the inner man it has been adopted. The quality and depth of Lewis's penetration of the great poet leaves all questions of satire limping along behind.
It is true, too, of his portrait of Edith Sitwell, completed in 1935. He both loved and loathed Sitwell. There was something about her own absurd self-posturing that may have appealed to him. "We are good old enemies, Edith and I," he once wrote, "inseparables, in fact." His portrait of her is all about the fragile, paper-thin grandeur of the posturing literary queen. She looks wonderfully colourful, but also mechanised amidst her slightly clownish clothes, as if she might be assembled from parts of herself. Vorticism began in mechanisation, the idea that human beings of the present could be represented most honestly as some errant species of barbarous machine.
Now, 20 years after the idea emerged, the breathing machine of Edith Sitwell has been tenderised, even humanised a little. Yet it is still absurd, clanking, and inclined, in the end, to rust. Lewis saw all this in his portraits. He saw how laughably horrible it all was, all this drawing-room flapping and flummery, and how, perhaps, it even deserved our limited pity.
"Wyndham Lewis: Portraits" is at the National Portrait Gallery, London WC2, until 19 October. For details log on to: www.npg.org.uk