Grierson fills the role vacated by Holly Ward, who was promoted to joint MD when Jonathan Sanchez moved to New York. He is now chief comms officer at Euro RSCG Worldwide's New York HQ (PRWeek, 16 June).
Grierson will head the agency's accounts for Jaguar, New Look, Diageo and personal-care products firm EC DeWitt. She is working alongside Melanie Charlesworth, who has been promoted to head of luxury and lifestyle.
Charlesworth joined from Aurelia PR in January.