Steffan Williams, formerly Porta’s managing director, is stepping up to chief executive.
He is taking over from founder David Wright, who will become chairman, a role being vacated by entrepreneur Bob Morton due to “health issues”.
Non-executive director John Foley steps up to become the senior independent voice on the board.
"I am pleased to announce that Steffan has taken on the CEO role to lead the next chapter of Porta's development, supported by the board and myself as chairman,” said Wright.
"The strength of the platform that we have built is allowing us to add to the quality of our senior team across all geographies.
“This accumulation of talent is allowing us to be considered for and to win ever more significant client assignments.
“Steffan's initial focus will be to ensure that this positive momentum continues to gather pace.
"I would also like to thank Bob Morton for his very considerable contribution as chairman to date.
“It's no exaggeration to say that without Bob's support Porta would not have achieved the rapid growth shown to date."