Southwark LBC chief executive Annie Shepperd is stepping down, the council has announced.
Ms Shepperd, who will leave the authority in May 2012 after nearly six years in post, said she was leaving to explore other opportunities and spend more time with her family.
The council said it was carrying out a review of its senior management structure and that there were “no immediate plans” for recruiting a successor.
Ms Shepperd, said:“I would like to say an enormous thank you and pay tribute to the councillors and staff that I have had the privilege to work with since I arrived, and will continue to serve the borough to the best of my abilities until I leave.
“This is a job I have loved doing and given heart and soul to and it is with some sadness that I have taken this decision.”
Council leader Peter John (Lab) said: “On behalf of the Cabinet and everyone at Southwark council, I would like to pay tribute to the contribution that Annie has made in serving this borough and helping us to deliver our priorities.
“On a personal level, I have enjoyed working with her very much and admire the enthusiasm she brings to the role. I would like, on behalf of the borough, to wish her the very best for the next exciting chapter of her life and to say that she will be missed by many in Southwark.”