35 WOMEN UNDER 35 2016: Katie Grosvenor, 35

Grosvenor started at media agency MediaCom as a PA in 2004, before becoming its youngest ever UK marketing director and now global operations director – one of only three women to hold this position in a network of over 6,000. As well as leading her team to secure £713m of new business over five years, she helped launch the firm’s apprenticeship programme.