MILLWALL have announced chief executive Andy Ambler is leaving the club to take up a full-time position with the Football Association.
He will be the FA's head of professional game relations.
Ambler told the club’s official website: "I have enjoyed my time at Millwall immensely and wish everyone at the club and the fans every success going forward.
"Millwall is a fantastic football club and I have been very proud to have represented it during my time at The Den.
"Over the next few weeks I will be working tirelessly to ensure that the transition period leading to the arrival of my successor is a smooth one. The club is in a very healthy state with an excellent chairman who remains as dedicated and committed as ever.
"Under the management of Neil Harris this exciting young Millwall squad has the potential to return to the Championship in the foreseeable future and I will continue to follow the club's fortunes with great interest.
"In terms of my new position at The FA, it is one I am excited about and I look forward to a fresh challenge."
A former director at Fulham, Ambler joined Millwall in March 2007 as chief executive.
He was elected to represent League One clubs on the Football League Board in June 2015, where he worked with then Chairman of the Football League, Greg Clarke, the new FA Chairman.
The club said it will announce news of his successor “in due course”.