The move allows Publicis to create a UK Starcom MediaVest Group in conjunction with MediaVest, its other wholly owned agency.
Publicis will operate the group as one legal entity, but the agencies will continue as two operations, working from two locations and with separate identities; Starcom Motive will retain its name, but MediaVest becomes Starcom MediaVest.
"It no longer made strategic sense for us or Starcom Motive to own shares in a single office in the Starcom network," Nigel Bogle, the chief executive of BBH,explained.
Following the acquisition, Starcom MediaVest will relocate from its West Kensington headquarters to new premises on Whitfield Street. Starcom Motive and Starcom MediaVest will share some back-office functions - including finance and IT - but will continue to operate their own planning and buying services.
"In maintaining two locations and two full-service offerings, we believe we are best positioned to expand the group's share of the UK market. There are no plans to move to one single entity," Mark Cranmer, the Starcom MediaVest chief executive for Europe, the Middle East and Africa, said.
The management line-up of the two agencies will remain unchanged and it is likely Jim Marshall, the chief executive of MediaVest, will retain a key executive role.
BBH remains 51 per cent privately owned and there are no plans for Publicis to increase its stake in the agency, or for BBH to launch its own rival media agency.