John Pilger is a journalist, documentary maker and New Statesman columnist. His new film, "The War You Don't See", is in cinemas from 13 December and will be broadcast on ITV1 on 14 December. More details here.

The War You Don't See is about the media's role in promoting and sanitising contemporary wars. Why make this film at this particular moment?

I have been writing and making films about media and war for many years. Translating this critique to film, especially the insidious power of public relations, has been something of an ambition. Peter Fincham had just taken over as director of programmes at ITV two years ago and clearly wanted to restore some of ITV's factual legacy. He was enthusiastic about the idea; he also knew the film would be critical of ITV. That's unusual.

Since I first went to Vietnam as a young reporter, I have been aware of the rituals and undercurrents and pressures within journalism that determine the news as much as the quality of the news itself. Broadcast journalism has a powerful mysticism; the BBC pretends that it is objective and impartial in the coverage of most things, especially war. The pressure to believe and maintain this pretence is almost an article of faith. For the public, the reality is very different. The University of Wales and the montoring organisation Media Tenor conducted two studies of the TV coverage in the lead-up to the invasion of Iraq. Both found the BBC overwhemingly followed the government line: that its reporting of anti-war views amounted to only a few per cent. Among the major western broadcasters, only CBS in America had a worse record. The public has a right to know why.

Why do you think journalists who reported on the Iraq War - a number of whom you interview in the film - are now so willing to admit they did not do their jobs properly? What prevented them from realising that at the time?

The atmosphere has changed. No one is in any doubt now that the reasons for the invasion of Iraq were fraudulent, as are the reasons for invading Afghanistan, as were the reasons for invading Vietnam. Still, the journalists who describe in my film were it all - and they - went wrong are courageous. I asked a number of others to appear, such as Andrew Marr and Jeremy Paxman, and heard nothing back. Indeed, the more famous the name, the greater an apparent unwillingness to discuss why, as Paxman told a group of students, they were "hoodwinked".

Do independent online sources - Wikileaks being the most prominent example at the moment - allow the public to bypass corporate media entirely?

Yes, but remember the public's principal source of information is still television. The main BBC News programmes have enormous influence. Certainly, as Wikileaks has demonstrated, the agenda of the "mainstream" is increasingly guided by the world wide web. For me, as a journalist, the web offers the most interesting and often most reliable sources because they are shorn of the consensual bias, and a censorship by omission, that pervades broadcasting.

Understandably, your focus is on war reporting. But the film also suggests that our entertainment industry plays a role in disseminating propaganda. How can that be effectively countered?

There is no propaganda machine like Hollywood. As Ken Loach pointed out recently, the great majority of movies in British cinemas are American, or British with American funding. This has led to the appropriation of both fact and fiction: of art itself. Edward Said describes the effect in his book Culture and Imperialism, pointing out that the penetration of a a corporate, imperial culture is now deeper than at any time. How do we combat it? We support independent film-makers and independent cinemas and distributors. We begin to think about journalism as a "fifth estate" in which the public plays a part and media organisations are held to account.

Even when the harsh reality of war is reported truthfully and accurately, audiences can simply choose to ignore it. Are there particular techniques you pursue in your film-making to avoid this happening?

Surely, the responsibility of persuading and challenging people, of exciting their imagination, belongs to us film-makers and journalists. Blaming the public is an admission of our own inadequacy. My experience is that people will respond positively if you make the connection with their own lives, or attempt to articulate the way they worry about the world, its wars and other upheavals. If you call power to account with facts, you get the reward of support from an audience. In other words, when people realise you are their agent, not an agent of a monolith called "the media", or of other powerful interests, they give you their time and interest. That makes journalism a privilege.