Banks was promoted from business director to managing partner only six months ago. She has been given the new job following the departure of the chief executive, Cheryl Giovannoni, last month. Giovannoni ran the account management team as part of her chief executive brief but O&M has now decided to separate the role.
Banks will report to Annette King, O&M’s UK group chief executive, until Charlie Rudd starts as O&M London’s chief executive in the new year.
Banks joined the agency in 2005 as an account executive. She progressed to account manager and then account director in 2007 and became a business director in 2011. She was made a managing partner in April.
King said: "There was an overwhelming consensus from within the agency that Marina was the best person for this role. Her drive and passion for the job, coupled with her popularity among clients and her peers, make her the ideal choice to lead the department as we head to Sea Containers, our new home."