Brien (pictured) joined Creston in 2004 as chief operating officer and chief financial officer, and was promoted to group chief executive in 2014.

Creston Group was sold to DBAY Advisors last year, According to the announcement, Brien will assist with the transition to private ownership until the end of April 2017. 

"After the successful sale of the company at an attractive premium for shareholders and agreeing the next phase of the Group’s journey, I believe now is the right time in my career to seek new challenges," said Brien. "I am confident my colleagues, along with DBAY’s support, will build on the success we have achieved to date."

A DBAY spokesperson said: "We want to thank Barrie for his vision and energy in growing the company over the years and wish him well in the next stage of his career.

"The management teams in our agencies will continue to innovate, create and deliver great results for all of their clients and the board will continue to be chaired by our colleague Iain Ferguson.”