Ms. Walsh joined United's precursor, Red Cell, in 2004 when it was made up of 62 agencies. This number has since been cut to nine offices as WPP sought to create a competitor to agencies with micro-networks such as Bartle, Bogle, Hegarty; Wieden & Kennedy; and Fallon Worldwide.
"You don't need two chief executives to run a micro-network," Ms. Walsh said. "It is right and proper that Andy stays as sole leader."
Separately, Steve Henry, who was chairman of HHCL/Red Cell before the transition to the United micro-network, is moving to TBWA London to become executive creative director. TBWA has been looking for a U.K. creative chief since the departure of Chairman Trevor Beattie last year to open his own London agency.
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