I am writing this on Monday morning, so what I say may be overtaken by events. But as I write, Ken Bigley is still being held by the Islamic terrorists in Iraq.

If I were the evil Abu Musab al-Zarqawi, who is in charge of Mr Bigley's unlawful incarceration, what would I do next? I would release Mr Bigley and issue a video on an Islamic website with me, Abu Musab, smiling and saying: "In the name of Allah the merciful we are setting this man free". The video would include footage of Mr Bigley in captivity enjoying a meal provided for him by the terrorists.

To do this would be a masterstroke for Abu Musab. It would be a double triumph with double the publicity. First he got all that news coverage when he took Mr Bigley prisoner. He would get as much publicity, if not more, by releasing him.

Abu Masub has gained the scale of publicity for his cause for which commercial companies would pay millions - only Masub has got it all free. No wonder he and his terrorist gang are chortling up their sleeves.

I have been ashamed of the activities of some of my colleagues in the mass media. Every TV and radio news bulletin, almost every newspaper edition, has led on this story, milking it for all it's worth. Tear-jerking has been raised to the level of an art form.

It is disgusting in particular the way TV channels have turned this appalling kidnapping into terrorism-as-soap-opera. It has been - and as I write it is still going on full belt - like an evil version of Big Brother.

And what is the result? It is to give undeserved prominence to evil men. Worse, it has taught terrorists that kidnapping pays; and so it has made it certain that other innocent people in Iraq are in danger of suffering the same fate as Mr Bigley. The undeniable truth is that the media's conscienceless self-interest in newspaper sales and TV ratings is endangering lives unnecessarily.

I have heard editors and programme-makers attempt to justify their coverage of this hostage-taking on two grounds. First, that these terrible events are "in the public interest". Wrong. There is a difference between the public interest and what interests the public. Second, it is said that the media must have freedom of speech. True. But freedom of speech requires the wise and prudent use of that freedom.

We now live in a world of instant global communications in which everyone, at the click of a mouse, has access to a worldwide audience. Our enemies use this capacity to do us ill. The media cannot claim a neutral role and pretend it is simply reporting events. For the truth is that the reporting affects the course of these events.

We journalists are not above the law and we are not magically free from the constraints of what is right and wrong just because we are paid to write or talk. We may not like it, but we are not mere spectators at some fascinating game: we are part of the game. The terrorists will note our every word, every picture, and use them for their own evil ends. We should all take to heart the Second World War slogan: "Careless talk costs lives".

* Peter Mullen is Rector of St Michael's, Cornhill, in the City of London, and Chaplain to the Stock Exchange.