 Kay organised and oversaw multiple clinical trials funded by the Medical Research Council relating to leukaemia treatments and served as secretary to the MRC's Leukaemia Committee from its founding in 1968 to its disbanding to 1977.Other MRC trials that Kay coordinated at the Royal Marsden focused on multiple myeloma and polycythaemia rubra vera.He was editor of the "Journal of Clinical Pathology" from 1972 to 1980.