Kinetic, half of which is owned by WPP and half by its management team, won the business after a lengthy pitch against Concord. The move aligns Unilever's outdoor business within WPP alongside all its other media planning and buying, which is with MindShare.
Despite the loss of its biggest client and the largest outdoor account in the UK, the Concord chairman, Alan Simmons, said his company is still viable. It has clients including Masterfoods, Nestle and, from 1 January, Peugeot.
Simmons said the Aegis-owned Posterscope, which bought Concord in August, was committed to maintaining Concord as a "second front door to develop more direct business and to cope with conflicting business".
He added that Concord is looking at moving staff on the Unilever account elsewhere within Aegis. "As the decision was not entirely unexpected, we have a contingency plan where there is no need to jettison people," he said.
Nigel Cowlin, Unilever's head of media and communication, said: "Our work in outdoor media planning and buying has been very effective until now, but Kinetic made a particularly strong case."
A Concord statement said: "We are confident that as part of Aegis/Posterscope we had made Unilever an unbeatable offer. Clearly though, it wasn't enough to counteract the WPP alignment issue. But we have enjoyed an excellent relationship with Unilever, and we look forward to welcoming them back."