[2] Thornton was a sculptor linked to the celebrated Geometry of Fear group which redefined the medium in post-war Britain.
He considered line rather than mass to be the expression of a more urgent fleetingly emotive quality in the uneasy atmosphere of the immediate post war years.
Thornton sculpted in metal having been inspired by the idea of making three-dimensional equivalents of the drawings of Rembrandt, which he hugely admired.
This he achieved by welding “a little comb” of tiny, fine metal rods to emulate Rembrandt's cross-hatching, a theory he successfully put into practice in one of his earliest sculptures, Roundabout 1955, Peggy Guggenheim Collection.
In 1955, Thornton joined Eduardo Paolozzi, Kenneth Armitage and Elizabeth Frink for the British Council's internationally touring Young British Sculptors exhibition, and the Institute of Contemporary Arts included some of his work in their New Sculptors Exhibition in London.