Since 2005, Ingram has been splitting her duties as the chief executive of Grey with a role running WPP's Team P&G. However, it is felt that the London office now needs a dedicated chief executive.
This role will include responsibility for Grey London as well as Joshua/G2. Ingram will remain as the chief executive of the Grey UK Group until a successor is found.
She denied rumours that the agency's chairman and executive creative director, Dave Alberts, and the executive planning director, John Lowery, were leaving the agency.
"I feel immeasurably proud about the progress that we've made at Grey," Ingram said. "It was a tough role to walk into, but to double profits was a great job. I'm looking forward to working with P&G to reinvent marketing communications in the future."
In her new role, she will marshall all of WPP's global relationships with the world's largest FMCG company. At Grey, she replaces Neil Kriesberg as the pointman on P&G. He retired at the end of 2006.Jim Heekin, the chairman and chief executive of Grey Global Group, said: "Tamara's appointment is the beginning of a new chapter in our partnerships with P&G. She is a natural, intuitive judge of what builds brands."