Although his work was the product of careful study and preparation, he wished always to convey a sense of immediacy and playfulness. "I like sculpture to look as if it happened, to express an idea as simply as possible," he said.

Born in Leeds of Yorkshire/ Irish descent, Armitage was influenced by both the Yorkshire landscape and visits to his mother's home in County Longford, in the Irish Republic. Nature played an important part in his early stylistic evolution. Later the Egyptian and Cycladic sculpture in the British Museum was another formative influence.

A scholarship from school took him in 1934 to Leeds College of Art, where Henry Moore and Barbara Hepworth studied before him. For Armitage, these were not fruitful years, as the college was then almost exclusively concerned with painting and graphic work. In 1937, he went on to the Slade school in London, where he received proper professional training in sculpture and, influenced by Brancusi, saw himself primarily as a carver, a notion he was later to reject.

During the war he served in the army, and subsequently taught for 10 years (1946-56) at Bath Academy of Art in Corsham. At the end of this period he destroyed all his pre-war carvings. He was now finding his mature style, beginning to make groups of figures in which a flat membrane envelopes upright or buttress supports. Two Linked Figures, People in a Wind (1950), now in the Tate Gallery, and Friends Walking are all fine examples of his most fecund and arguably most expressive period.

Armitage began to exhibit and gain recognition comparatively late into his career, when he was 36. He was reluctant to show his work before he was more confident of the direction he was taking. But after his first one-man show, at Gimpel Fils in 1952, his reputation quickly gathered momentum and was consolidated six years later at the 29th Venice Biennale, where he won the prize for the best British sculptor under 45. His international status had been further established in 1956, when he won first prize in an international competition for a war memorial for the town of Krefeld in Germany. From this period, Armitage showed regularly both in London and New York. In 1953, he took up the Gregory Fellowship at Leeds University.

Later, in the 60s, his sculpture would gradually become more plastic, massive and less frontal, as in Life Study, Reclining Figure and Roly Poly. He also began to model in clay in preference to plaster. His work was now being purchased by the Tate Gallery, the Victoria and Albert Museum, the Arts Council and British Council. From 1960 to 1963, he worked intermittently on a project for the central façade for the Chateau Mouton Rothschild, near Bordeaux. He was visiting professor at the University of Caracas, Venezuela, in 1964; at Boston University, Massachusetts, in 1970; and visiting tutor at the Royal College of Art from 1974-79. In 1969 he was awarded a CBE.

In this later period, he became involved with experiments in the conjunction of drawing and sculpture through the use of silkscreen and bromide images mounted on simple shapes and by the juxtaposition of small plaster figures and graphic backgrounds.

Armitage continued to exhibit internationally throughout the 80s. He held a large retrospective at Artcurial in Paris in 1985, exhibited at the Seoul Olympics in 1988, at the Yorkshire Sculpture Park in 1996, and at the Millennium Sculpture Exhibition, Holland Park, in 2000. He became a Royal Academician in 1994.

His wife Joan, whom he married in 1940, predeceased him.

Kenneth Armitage, sculptor, born July 18 1916; died January 22 2002.