The move has seen CNC’s London staff move to Capital MSL’s Whitfield Street office in the City. The new CNC operates 11 offices in eight countries and works on more than 200 accounts globally.
In a statement issued today, Campbell and Roland Klein, now joint managing partners of CNC in London and the Middle East, said: "Both companies share the ambition to be one of the world’s most successful international strategic communications firms, and the completion of our merger today moves us a step closer to achieving that goal.
"We have already started working together across a number of mandates in a number of markets and are excited about the opportunities ahead."
CNC was bought by MSL Group’s parent company Publicis Groupe in 2012.