Saunders' move to McCann comes eight months after he was asked to step down from his role as the chief executive of Red Cell. His departure paved the way for the incoming chief executive, Lee Daley, who is himself a former chief strategic officer for McCann's operations in Europe, the Middle East and Africa.
The move is the first major appointment made by Tamara Ingram since her arrival as chairman and chief executive of McCann-Erickson UK and Ireland last year. It fills the gap left by the former head of planning, Pascale Reed, who left the agency without a job to go to in May.
"The purpose of this appointment is to bring planning to the forefront," Ingram said. "Clients are looking for bigger insight and new and imaginative ways of communicating. It's no longer a 30-second TV ad for everything."
Saunders will be supported by two newly created joint planning directors, Cathy Samson and Andrew Serednyj, who are both promoted from senior planning director roles.
"Frankly, McCann just has so many good, big clients that when you do something interesting it becomes that much more visible, Saunders said.
"I find the people here energetic and committed. They are the kind of people that I would like to spend time with. A lot of advertising groups are groping their way towards joining up communications for clients but there aren't many with the strength and depth around the offer that McCann has."
Saunders joined Michael Bungey and Partners as a trainee in 1983 after working for the Labour Party when Michael Foot was leader. He spent seven years as a planning director at Ogilvy & Mather, working on the American Express account, before leaving to relaunch Conquest in 1996.
"Julian is a fantastic ideas man and in today's world our clients need ideas, Ingram said.
"He's also very collaborative in the way that he works and he has that huge brand experience that we absolutely need."