Caroline Bull, the chief executive of Oxford City Council, is to quit her £107,000 job in January to pursue "long-held ambitions".

Ms Bull, who joined the authority in 2004, released a statement in which she urged staff to continue the "blame-free" culture she had tried to instill at the council.

She succeeded Marion Headicar, who moved to Portsmouth City Council.

In a statement to staff this morning Ms Bull said: "I want to let you all know I will be leaving my post as chief executive in January 2007.

"I have a unique opportunity to achieve a number of long-held ambitions and I have decided to seize that opportunity.

"I will greatly miss many of the people I have worked with in Oxford, particularly the positive and customer-focused staff and managers at the council and the business leaders who have engaged so enthusiastically with our Oxford Means Business initiative.

"I hope the open, responsive and blame-free culture I have tried to promote at the heart of our improvement programme can be maintained and the council will continue to raise its game to help our city achieve its potential."

Ms Bull came to Oxford from Exeter, where she had been director of enterprise and innovation for the South West of England Regional Development Agency since 1999.

Before that, she was based in Reading as managing director of Business Link Thames Valley and commercial director of the Training and Enterprise Council, Thames Valley Enterprise from 1993.