BBC Trust chairman Rona Fairhead to exit after intervention from Theresa May
The former Financial Times Group chief executive revealed her intentions in a statement to The Financial Times.
Separately, a BBC Trust spokeswoman confirmed the news to Business Insider.
Fairhead was told in May by former prime minister David Cameron's government that she could stay on as chairman of a new BBC governance board, which forms part of sweeping governance changes at the corporation next year.
But in a u-turn, new prime minister Theresa May told Fairhead last week that she would have to re-apply for the position.
"The prime minister strongly encouraged me to take part in the new appointment process, for what would be a new four-year term as BBC chairman," she told the Financial Times.
"However, after much thought I have come to the conclusion that I should not do so. It is my belief that it will be better to have a clean break and for the government to appoint someone new."
Fairhead will remain in post until the governance changes are made. This will involve abolishing the BBC Trust and creating a powerful new board that will govern the British broadcaster.
Fairhead added: "I took on leadership of the Trust to help stabilise, strengthen and develop the BBC following a very difficult period in its history and through charter review. I am proud of what I and my colleagues, both at the Trust and the BBC, have accomplished during the past two years."