Southwark Council chief executive Annie Shepperd is to leave the authority after five years, it was announced on Friday.
Southwark Council staff were told on Friday morning that the borough's chief executive, Annie Shepperd, will step down from the Ł166,275-a-year role in May 2012.
"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," said Annie Shepperd.
"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. But I am also looking forward to new opportunities in work and in life.
"As a resident of the borough I am pleased I will be able to watch this council go from strength to strength, even in these challenging financial times. It really is a special place with many wonderful people from all walks of life."
In her message to staff Ms Shepperd listed the council's deal with Berkeley Homes for the sale of the Potters Fields coach park site and the Elephant & Castle agreement with Lend Lease among her achievements.
Council leader Peter John 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.
"We have no immediate plans for recruitment as we have plenty of time to consider what is best for the council and I already have a review of senior management structures underway.
"But, as before, our focus will remain on working hard with senior managers and all staff to deliver a fairer future for all."
Annie Shepperd joined Southwark Council from Wallsall Council in September 2006.