Having left the Slade to live in Paris, Turnbull returned to London in the early 1950s and in 1954 was selected by Herbert Read to represent Britain at the Venice Biennale. Alongside contemporaries including Robert Adams, Kenneth Armitage, Reg Butler, Lynn Chadwick, Geoffrey Clarke, Bernard Meadows and Eduardo Paolozzi, Turnbull showed in the now legendary exhibition entitled New Aspects of British Sculpture, which set him on a course to become one of the most celebrated and sought-after artists of his age.

To Turnbull, painting and sculpture were regarded with equal importance, and he worked on both concurrently throughout his career. In 1955 he was introduced to the prominent American collector Donald Blinken, who in turn introduced him to a number of the leading figures of the New York School, including Mark Rothko and Barnett Newman. Both artists were to influence Turnbull’s work, resulting in reductive and minimal explorations of the boundaries between gestural abstraction and hard hitting colour-field painting. This cross-Atlantic dialogue was to provide a continued source of inspiration for Turnbull, who during the mid-1960s became increasingly interested in the ideas of American Minimalist artists including Donald Judd and Sol LeWitt. Judd in particular advocated the creation of a new form of art which did not conform to the conventional tenets of either sculpture or painting - instead, the primacy of pure form itself was celebrated.

The resulting works were produced by Turnbull in a short bout of creativity that lasted a little over a decade, and marked in the late 1970s with a return to a more organic approach, the likes of which had dominated his work up until the early 1960s. Turnbull explored a variety of different metals and materials, including cut and painted steel and un-coated stainless steel. Sextet can be recognised as one of the most important, impressive and ambitious works produced during this period, chosen by the artist for inclusion in his major 1973 Tate retrospective and discussed in the body of the catalogue by Richard Morphet at great length. Here Turnbull found a new visual language for his continued exploration of the reciprocity of shapes and signs through the process of modular construction. Sextet conveys a great sense of strength and solidity, with six painted stainless steel elements arranged in a manner reminiscent of Neolithic stone circles, encouraging viewers to interact with each individual form and engage with the work in its entirety.