When he was called up after graduating, Richens became a conscientious objector, assigned, along with fellow biologists V. J. Chapman, R. A. Lewin and G. E. Fogg to a survey of the seaweeds on Britain’s coats, with a view to their possible use for making parachutes or feeding the nation.
Dr Max Coleman of the Royal Botanic Garden, Edinburgh writes, however (2009): "The advent of DNA fingerprinting has shed considerable light on the question.
A number of studies have now shown that the distinctive forms that Melville elevated to species and Richens lumped together as field elm are single clones, all genetically identical, that have been propagated by vegetative means such as cuttings or root suckers.
"[2] Although a professional botanist, Richens also had a personal interest in machine translation, carrying out important early work on the subject in collaboration with Margaret Masterman and Michael Halliday, and later at the Cambridge Language Research Unit.
He was an accomplished pianist and organist and was choirmaster first at the Cambridge University Catholic chaplaincy at Fisher House and from 1961 at Our Lady and the English Martyrs Parish Church.