JWT London will take the lead on the business, which will span more than 80 markets across the world. Debbie Huret, the former client services director on the Diamond Trading Company account, who led the pitch team, will run the business along with Craig Davis, JWT's chief creative officer, and Guy Murphy, the global planning director.
The win is the result of an eight-month pitch process, also involving DDB and Bates Asia/Grey.
It marks a transformation in the fortunes of JWT after a torrid 2006, in which it lost the Reckitt Benckiser account and Vodafone's UK business.
"It is such a big win for us both from a business and a psychological perspective," Jeffrey said.
JWT's appointment comes a month after Nokia named Wieden & Kennedy as the global lead creative agency on its £175 million handset account.