BBC director general Greg Dyke has warned of the risks of crossing the line between patriotism and objective journalism.
Dyke warned against BBC content being coloured by political influence
In a speech to a journalism conference in London, Mr Dyke denounced the "gung-ho patriotism" of one US network covering the Iraq war and said it should not be allowed to happen in the BBC.
He said: "If Iraq proved anything, it was that the BBC cannot afford to mix patriotism and journalism.
"This is happening in the United States and if it continues will undermine the credibility of the US electronic news media."
He said impartiality meant giving a range of views, including those that were critical of the government.
"We are here for everyone in the UK, a trusted guide in a complex world.
"We perform this role best by exercising the freedom to air a wide range of opinion and to report the facts as best we can. In doing so, far from betraying the national interest, we're serving it."
Speaking at Goldsmiths College, University of London, he said the Iraq war had presented journalists with a number of challenges.
These included more 24-hour news, the risks faced by embedded reporters and unattributed, unreliable information on the internet.
He said: "We must temper the drama and competition of live, rolling news with the considered journalism and analysis people need to make sense of events."
Commercial pressures may tempt others to follow the Fox News formula of gung-ho patriotism but for the BBC this would be a terrible mistake
The director general also rejected criticism from the government for keeping a BBC reporting team in Baghdad, saying: "The whole culture of BBC journalism is based on the drive for accurate and impartial reporting.
"And we must never allow political influences to colour our reporting or cloud our judgement.
"Commercial pressures may tempt others to follow the Fox News formula of gung-ho patriotism but for the BBC this would be a terrible mistake.
"If, over time, we lost the trust of our audiences, there is no point to the BBC."