The Norwegian, who has been at the helm of the agency's UK operation since early 2004, is relocating to his native Scandinavia to take an undisclosed in-house corporate affairs job.
He said: "My task in London is basically completed, having built a strong team and put the business back into growth." Heggenes told his two bosses - global CEO Mark Penn and Europe CEO Heidi Sinclair - of his decision last week.
B-M's corporate and tech MD Jonathan Jordan, who has been with B-M for just over three years, is to become interim UK CEO. He was apparently in the process of being promoted to "deputy UK market leader" when Heggenes resigned.
Sinclair said: "I have great faith in Jonathan, who will have a transition period with Per." She said a decision would be made at a later date as to whether Jordan would get the job full-time.
For full story see this week's PRWeek - out Friday 11 August.