Creative agencies Krow and Bigdog are to merge in October, creating a full-service proposition for brands including DFS, Fiat, Sky Vegas, Pret a Manger, Barclays and Aviva.
The newly merged agency, which will be based in Krow's existing office near Farringdon, will retain the Krow name and officially launch at the end of October. There are no planned redundancies, parent company The Mission said.
Krow was acquired by The Mission in 2018 in a deal worth up to an estimated £14.5m, when it had been the UK's second-largest independent agency, according to Campaign's 2017 School Reports. Last year, it was 16th in Campaign's list of top 100 agencies as ranked by Nielsen.
The merger is part of a raft of changes overseen by The Mission chief executive James Clifton, who said the group will be whittled down from 16 to 11 agencies as a result of two other mergers and some "rationalisation".
Creative shop Story, whose clients include M&S Bank and the NHS, will expand into Newcastle by taking over Robson Brown and will open a new office in Leeds.
Meanwhile, RLA, The Mission's specialist automotive agency, will become part of April Six, with the newly bolstered agency serving clients including Volkswagen Group and Groupe PSA, which owns Peugeot and Citroën.
The Mission, which said it had enjoyed eight consecutive years of growth, has also unveiled a new logo and changed its name from The Mission Marketing Group to reflect the fact that its services have evolved beyond "pure marketing", it said.
Clifton said: "Since taking on the role of group chief executive, my priority has been to look at how we can build on our position of strength and ensure that the business continues to grow and prosper.
"The new vision, identity and structure of our group not only reflects where we are today, but provides a platform for the future. This platform of ‘collaborative specialists’ harnesses the unrivalled talent that exists within our agencies."