The announcement ends months of speculation about the creative leadership of Britain's third-largest agency since Charles Inge quit 14 months ago to join what is now Clemmow Hornby Inge.
As the creative directors, Barry and Collins will report to Paul Weinberger, the chairman, who will continue to take responsibility for the agency's showpiece £26m Tesco account.
The agency was in advanced talks with another, external, candidate, but these drew to a close last week.
Weinberger, who celebrates his 50th birthday this week, had been the acting executive creative director while the succession was secured. "Paul has no plans to retire," Chris Thomas, the chief executive of Lowe, said. "But he doesn't want to continue doing the whole thing."
The promotion of Barry and Collins follows Lowe's tradition of never having appointed an outsider as creative chief since it was established in 1981. It comes two years after Inge hired the pair.
Since then their work has included the "blackmail" Heineken commercials featuring Paul Daniels and Debbie McGee, the launch campaign for Tesco's Cherokee range of casual clothes, and the launch advertising for Nestle's Double Cream.
Lowe, which was rebuffed last summer in its efforts to replace Inge with Nick Bell, the Leo Burnett joint creative director, offered the role to Barry and Collins six months ago. "We felt they were the natural successors but they felt they weren't ready for the job," Thomas said.
Barry and Collins' appointment, which will see them take control of 22 creative teams, follows what has been an eventful period for Lowe. The agency has been battling to defend its share of Vauxhall's £60m UK account against its rival roster shop, Delaney Lund Knox Warren & Partners, and this month resigned its £43m Orange business because of problems.
Barry, a writer and former deputy creative director of the Wieden & Kennedy office in London, is known for his work on Nike and M&C Saatchi's "catisfaction" campaign for Whiskas. Collins, a former Campaign Face to Watch, worked with the writer Mary Wear at FCB, Gold Greenlees Trott, Saatchi & Saatchi and Abbott Mead Vickers BBDO.
Barry said: "We'd only been at Lowe 18 months when we were offered the job but we'd never been creative directors before. But we like the agency and want to play a long-term part in it."
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