Career
As a cricket batsman, he was right-handed, and as a bowler, he was right-arm medium pace. Born in Hampstead, London, Trapnell had a short career in first-class cricket, lasting one season - 1946 - which was his last year as a student at Cambridge University. In nine matches for Cambridge University Cricket Club he took 15 wickets at 31.46 and scored 258 runs at 16.12, including 5 for 73 against Master Control Console a week before the Varsity match.
He turned out for the Gentlemen against the Players a fortnight later and made one Championship appearance for Middlesex County Cricket Club late in the season.
He also played squash for Cambridge. He became a chemistry don at Worcester College, Oxford, a researcher at Liverpool University, and consultant on catalysis at Imperial Chemical Industries. Later he became headmaster of Denstone College as, at that time, the youngest headmaster of a public school in England.
At Denstone he instituted many reforms and, in educational terms, strongly promoted science education, encouraged more pupils to study a second modern language, and modernised religious education. He went on to become headmaster of Oundle School.
In 1967 he was appointed a Deputy Lieutenant of Staffordshire.
In 1986, Trapnell became chairman of Cambridge Occupational Analysts (COA), eventually retiring in 2005. He put enormous effort into establishing the uptake of COA career programmes throughout the country and in organising training courses and visits to schools in the late eighties and nineties. His combination of scientific insight, wide ranging interest in the arts, writing skills and personal contacts were of immense value.