The famously direct chief executive of COI is leaving with no job to go to and five months after her three-year contract expired.
She said: "I've worked my whole contract and I stayed after that to complete the five-year review which was the most successful we've ever had. I feel I've achieved an enormous amount and now it's time to go back into the big wide commercial world."
Fisher, 48, succeeded Tony Douglas as the chief executive of COI in 1999.
She embarked on an energetic reform of the body to see work placed with it by government departments rise by 50 per cent in a year, and creative standards improve on the back of some typically difficult government briefs.
COI created its first strategic planning roster during Fisher's tenure and it won Campaign's Advertiser of the Year award for 2001.
Fisher has worked as a product manager for Reckitt and Coleman Leisure, as the RHM Foods brand manager for Bisto and as a senior marketing manager at Grand Met. She was appointed as the marketing director of Holsten Distributors in 1989 and was the general manager, marketing and commercial, for Courage International between 1994 and 1995. When she was made redundant following a takeover, she moved into radio sales at CLT UK. After another spell of redundancy, when CLT sold off its UK radio interests, she joined COI in 1999.
Her role was expanded in February this year when she was named as the Government's chief advisor on marketing communication and information campaigns. She now reports to Alastair Campbell, Tony Blair's director of communications and strategy, marking a controversial extension of his remit.
Fisher hopes her next job will be in advertising or media. "I'm cheerful and optimistic, she said. "I feel I've got a unique background and an understanding of all areas of the advertising and media world."
The industry was shocked last autumn when the Department of Transport and the Regions decided to opt out of COI and build creative and media rosters of its own.
The move was a blow for the agencies that had just clawed their way on to new creative and media planning rosters. However, in May this year, the DTLR opted to split its £20 million advertising account between a roster of six agencies, all of which would have been available through the existing COI roster.