The pair, best known for their TV work on Waitrose, declared their intention to go amid a revamp of the agency's management front line aimed at improving its profile. They are expected to leave by the end of the year.
Hoggins and O'Shea, who helped found BHO 13 years ago, reverted to a part-time arrangement last year, allowing them to concentrate on Waitrose. However, they returned to caretake the creative department earlier this year, when the creative directors, Rob Fletcher and Dave Alexander, left.
The stopgap arrangement lasted until the arrival of Al Young from HHCL/Red Cell three weeks ago.
John Banks, BHO's chairman and chief executive, said: "With a new management team in place, Ken and John felt the time was right for them to do other things and I understand that perfectly."
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