Gilly studied Microbiology and Immunology in the 1960/70s in London. She began her career in R&D at the Lister Institute of Preventive Medicine, followed by 2 years in the Pathology Department at Bedford Hospital. In 1976 she moved to the pharmaceutical industry, joining Hoechst Animal Health in R&D, developing veterinary vaccines and pharmaceuticals. She transferred into Regulatory Affairs in 1981, where she gained experience in putting new products through the Concertation and Mutual Recognition procedures both in the UK and in Germany. After 4 years at the German HQ of Hoechst she returned to the UK in 2000 to join Aquaculture Vaccines Ltd. In 2002 she became Director of Regulatory Affairs for Pfizer. Gilly has been chair of the NOAH’s Biologicals Committee and a member of the IFAH Biologicals Committee. She retired from Pfizer in 2010 and is now a consultant involved in harmonising registration requirements and setting up a Mutual Recognition Procedure in East Africa, funded by GALVmed.