MDs Joe Walton and Dave Woodward, and director Charlie Meredith-Hardy have left the agency to launch a new firm early next year.
Walton took over as MD of the tech practice at the start of 2016. Together with Woodward and Meredith-Hardy, they have helped secure a host of new briefs, including IBM and Epson.
Walton said: "After a combined 32 years with the firm, we are leaving Weber Shandwick and will be officially launching a new B2B-focused agency together in 2020.
"Weber Shandwick is an outstanding firm and we’ve loved every minute of our time there. Now it’s time for new beginnings and a shot at building something really special. Stay tuned for more."
Weber Shandwick London MD Helen Bennet MD said the trio leave with the agency’s best wishes in their new endeavour.
She added: "Our B2B and tech practice continues to go from strength to strength under the leadership of Laura Tapper, who was promoted into the MD role earlier this year. Trapper has been central to the development of our integrated B2B and tech marketing offer and the development of a high-performing and results-driven team."