Just weeks ago Jonathan Shore, MD of sister WPP agency Cohn & Wolfe, was installed as Wheeler's boss as part of a new holding company that straddles the two agencies globally (PRWeek, 7 October).
Wheeler, who heads GCI's work for European clients British Airways, Novartis and Dell, plans to work independently in the UK and on the Continent.
Shore has effectively already replaced Wheeler as GCI UK CEO, despite continuing to run Cohn & Wolfe UK.
Wheeler said: 'Jonathan has handled the alignment of GCI and C&W with the greatest acumen and sensitivity. I hope to maintain a constructive and cordial relationship with my ex-colleagues.'