Martin Perry has stepped down as chief executive of Brighton and Hove Albion after 15 years.
He will stay on the board of directors although managing director Ken Brown has left.
Derek Chapman, a long-serving director, will be temporary chief executive officer (CEO) until a permanent replacement for Mr Perry has been found.
The boardroom changes also see Robert Comer standing aside from his role as finance director (FD). He will keep his boardroom seat while his replacement as FD will be David Jones.
Mr Perry, 64, will continue to be the chief executive of The Community Stadium Limited as he oversees the plans to add 8,000 seats to the Amex.
The role also involves leading the project to build a new training ground and academy in Lancing.
The club issued a statement which said: “Ken Brown is leaving his role as managing director to pursue his career elsewhere.
Commitment
“The club’s board of directors would like to thank Ken for all his work and commitment over the last four years and wish him every success going forward.
“In addition, Martin Perry has given the board early notice that he wishes to retire in July 2014 following completion of the expansion of the Amex and the construction of our new training ground and academy.
“He is relinquishing his role as CEO of BHAFC but remains as an executive director. He will continue as CEO of The Community Stadium Limited, retaining overall responsibility for the two key projects.
“Martin’s personal contribution to the club has been enormous over the last 15 years and we would not be where we are without his efforts.
“The board will recruit a CEO for the football club and in the interim long-serving director Derek Chapman will take on the role of interim CEO.
“He will be responsible for the day-to-day running of the football club until the new CEO is in place.
“Robert Comer has for many years combined his role as partner of his accounting practice with that of being finance director of the club.
“The growth in business due to the club’s move to the Amex has resulted in the FD role becoming full-time.
“The club is delighted to announce that David Jones will join the board as finance director.
“The club would like to thank Robert for his excellent contribution to date. He will remain a board director.”
