Pattison (pictured) will take on the role in addition to her existing position as chief transformation officer at GroupM, WPP’s media buying division.

She will be responsible for overseeing the company’s top 50 global client teams, and getting the group’s agencies to work more closely together, as part of WPP’s aims to simplify its offering – a strategy chief executive officer Sir Martin Sorrell has called ‘horizontality’.

Pattison was appointed to the GroupM transformation role in May, prior to which she was global chief executive of Maxus. Previous experience includes roles at Young and Rubicam, PHD Media and Sony Ericsson.

The appointment comes at an important time for WPP, which has reported falling net sales for the past two quarters. The company, along with other agency groups, is feeling the effects of large clients lowering their marketing spend.