BBC director-general Tony Hall (pictured, Reuters) has warned staff the corporation's independence will be challenged and it will face "naked bullying" in the run-up to the general election and next year's charter review.
It was a moment of "high risk" for the corporation, he told staff in central London.
"And there may be some – I hope only a few – who try to use the impending charter review to influence our coverage of politics in this most sensitive of political years. We will never let that happen, because to do so would betray the public and the ideals of the BBC," he said.
He accepted that the corporation would "get things wrong", adding: "It's inevitable – and we will reflect and put things right where we have.
"But we will never confuse justifiable complaints with naked bullying.
"There will be others who just want to join in a vital debate about public broadcasting with ideas for change and reform. I want them to know that we will listen and learn and reflect on what we hear."
Hall appealed to staff to "help us make our case" by "spending every penny of the licence fee as if it were your own" and "by speaking up for the BBC against those who would bring it down".
The BBC came under pressure last year over the future of the licence fee and Culture Secretary Sajid Javid has warned "more can and must be done" to make it more efficient.
The corporation, which has axed hundreds of jobs in recent years in a bid to save hundreds of millions of pounds, has warned the Government not to rush in to a review of the licence fee.