Prime Minister David Cameron quipped that he would close down the BBC while talking to journalists in the run-up to the general election.
BBC political editor Nick Robinson said the comment was relayed to him by colleagues.
Robinson told The Guardian he wasn’t sure whether the comments were a joke, adding: “What really matters is the impact it has on other people.
“Some people on the bus regarded it as funny but they generally didn’t work for BBC.
"The people who did [work for the BBC] regarded it as yet another bit of pressure and a sort of sense of ‘don’t forget who’s boss here’.”
The story is revealed Robinson’s book Election Notebook.
In it, he says: “What the PM is alleged to have told the DPM is that he knew the Conservatives couldn’t win a majority at the election. The Lib Dem subtext, of course, is that if they can’t win you might as well vote for us to keep them honest.
“News reaches me from the Tory campaign bus that the PM marched on board and called the story ‘rubbish’. When one hack jokingly muttered ‘bloody BBC’, the PM responded, ‘I’m going to close them down after the election!’
“Joke? Expression of frustration? Threat? All three?
“No one could be sure. In a few weeks’ time working out what it was could really, really matter.”
Explaining why he didn’t report the story at the time, Robinson said on Twitter: “I was in hospital when it happened. Didn’t get quote or second source till post polling day.”
Press Association political reporter James Tapsfield said on Twitter: “I don't think there was any doubt he was joking.”
Speaking at a conference earlier this month BBC head of news James Harding said: "I was, I admit, quite astonished by the ferocity and frequency of complaints from all parties. More often than not, it was some version of a politician saying either I want ‘more me on the BBC’ or ‘my side of the story is the story’.
"And this being my first election at the BBC, I was struck by how many politicians and spokespeople paid lip service to the idea of the BBC’s editorial independence, but, nonetheless, did think it was their place to say what should be leading the news, what questions should be asked and how, how they wanted audiences to be chosen for programmes.”
He added: “I’ve been asked whether politicians made the link between the BBC’s election coverage and the future funding of the BBC? Mostly, not. But, along the way, there were people from all parties who made the connection between their dissatisfaction with the election coverage and the fact that the next government will set the licence fee and the terms of the Royal Charter.
"Some did so explicitly. Nigel Farage, for example, said he was unhappy at UKIP’s treatment on the BBC and proposed cutting the licence fee by two thirds. Others left it hanging in the air.”