Art - Tom Rosenthal celebrates work old and new by Ireland's most versatile artist

Louis le Brocquy, at 85, is undoubtedly Ireland's most senior painter. He was born in Dublin, but his name comes from his Belgian grandfather. Although a serious artist, he lacks self-importance. "I'm aware that my age and venerability could be mistaken for some kind of authority," he recently said.

After a longish quiet spell during the decades when figurative art had gone out of style, he now rejoices in renewed success, with major early works selling for seven-figure sums at auction. None of this affects the way he paints his unfashionable, endless variations on the human body and, above all, heads, preferably male and literary.

According to A Painter Seeing His Way, his wife Anne Madden's account of his life, le Brocquy destroyed much of his work in 1963 after a period of depression. Then, in 1964, a visit to the Musee de l'Homme in Paris proved both seminal and catalytic. He was overwhelmed by the painted clay Polynesian and Melanesian heads, and was struck by the idea of a "ritualistic laying-on of hands, a recognition of the ancestor's entity; palpable marks from the outside which defined and celebrated the spirit within the reconstituted ancestral head".

His obsessive painting of head images, usually within a restricted, essentially blue/grey palette of exquisite subtlety, became the core of his work. Within that were imaginary versions of people he had never met, ranging from Wolfe Tone to Ibsen, Strindberg and Lorca, but most of the time they were portraits of those he had known or befriended in Dublin, London or Paris. Picasso is there, and Francis Bacon, but his most exhaustive explorations of physiognomy are literary. Reading Joyce or Yeats or Heaney, but particularly Beckett, recalls le Brocquy's iconic heads.

Le Brocquy has two shows running concurrently in London. His latest paintings are at Gimpel Fils and his tapestries are at Agnew's. The paintings are uncharacteristically based on whole bodies, and not just heads. All the figures are generic nudes, several occurring in triptychs. In one, a full-frontal male is flanked by his two profiles, like a man contemplating himself in a tailor's multi-mirrored fitting room. Among the solo figures is one with a red mark, which recalls the artist's vision of an exposed pituitary gland, observed when the young le Brocquy watched surgery to make anatomical drawings for medical textbooks to pay for paints and canvas.

The tapestries at Agnew's are particularly impressive. Le Brocquy was a disciple in this medium of Jean Lurcat (1892-1966) who, having studied the medieval tapestries at Angers, single-handedly revitalised the tradition of graded tones and detailed numbered cartoons. Unlike the much-vaunted Graham Sutherland tapestry in Coventry Cathedral (which is, I suspect, simply a giant, weaver-magnified copy of a smallish gouache), le Brocquy's coloured tapestries are created specifically for the techniques of Aubusson. Those from the 1950s, notably Adam and Eve in the Garden, are completely different from his paintings, and while other artists have been happy to have their images merely copied by the lissier, le Brocquy has thought, from the outset, like and for the weavers - and it shows.

He is also a formidable book illustrator. Taught as a boy by Elizabeth ("Lolly") Yeats, the sister of W B and Jack, and a pillar of the Cuala Press, he made an immaculate, prizewinning drawing of the arms of Dublin. He drew them again, 55 years later, as one of his illustrations for the Dolmen Press edition of Joyce's Dubliners, a perfect livre d'artiste that ranks with Matisse's Ulysses as the best of all the illustrated Joyce books.

Le Brocquy's greatest book is his series of black-and-white sketches for Thomas Kinsella's 1969 translation of the eighth-century Ulster epic The Tain, drawings he turned into full-scale tapestries. Their impact, in an apparent monochrome on a creamy background, is stunning. The monochrome is in fact an infinitely subtle mix of different blacks and dark browns, and the imagery of warriors, women and animals, of people dancing, massing into armies and fighting, is so immediate that one thinks they were done in relief. They are not; they are only woven, but they remain a most tantalising and vibrant version of an old myth.

Louis le Brocquy's Aubusson tapestries are at Agnew's (020 7629 6176) and recent paintings are at Gimpel Fils (020 7493 2488), both until until 29 May