Lynton Charles said I was to debate what Linda Lovelace was to pornography - the only mouth in town

Talk about feeding the hand that bites you. Scarcely a month goes by without this otherwise illustrious organ exposing me to abuse and/or ridicule on one spurious basis or another. Then someone asks me to write a diary. And here I am doing it. Odd, eh?

Just in case Nick Cohen is reading this, it's not for the money. You'd starve very quickly if you relied on occasional fees from this tight-fisted bunch. Still, mustn't grumble. The BBC is not ungenerous and, oddly enough, there's always someone out there wanting to hire the services of an ageing hack and pay over the odds.

I only mention Nick Cohen because he has been one of my tormentors. He once posed as a potential client and managed to track down my agent to find out how much I got paid. Too much - or so he concluded. Only one problem: I don't have an agent. Can't see the point of them. So, Nick, you were conned. And anyway, I'd never work for the pathetic fees the impostor quoted you.

Not that I mind too much. Nick Cohen is a serious, crusading journalist and probably a decent bloke, and we all make mistakes. Which is more than I can say for that snivelling creep Lynton Charles.

Ever since Charles blagged his way into getting his sad little diary published in these pages, he has been having a go at me one way or another. I suppose Alastair Campbell puts him up to it. Charles even said last week that I "fundamentally believe" that I would make a better prime minister than anyone younger than me.

Very hurtful, that was, especially bearing in mind my poor showing in the NS Fantasy Cabinet stakes. The competition was rigged, of course. My name appeared right at the bottom of the list of candidates, squeezed in between Catherine Zeta-Jones and Anna Kournikova. There are worse places to be squeezed, I suppose.

I knew Lynton Charles had it in for me from my first appearance in his column. He compared me to Linda Lovelace, which gives you some idea of the way the sad git's mind works. He said that I was to public debate what Lovelace used to be to pornography - the only mouth in town.

When I was based in New York, 30 years ago, Lovelace was a national hero for her seminal performance in Deep Throat. Cinemas showing hard-core were pretty new in those days. Bambi was about as raunchy as it got. So a gang of us took a rather prudish girl from the office to see Deep Throat for a surprise birthday treat. Some surprise. She probably thought it was about Watergate. I sat on one side of her. She wasn't so much shocked as stunned. I didn't know it was possible for a human to go without taking a breath for 85 minutes. Even Lovelace came up for air occasionally.

So when will hard-core movies start appearing in our cinemas? It can't be much longer, now that some video shops can legally sell the dreary stuff. What with that and Lord Rogers wanting our cities to be designed to accommodate prostitutes, we may finally be on our way to some more sensible laws governing porn and prostitution. Any system that, in effect, forces women on to the streets, in the way that ours does, has to be crazy. I'd vote for anything that made life more difficult for the pimps.

As I'm using this diary to attack an enemy, let me defend a friend. John Sweeney implied in a letter last week that John Simpson had been less than courageous for most of the Kosovo war, because he reported from Belgrade. That was un- worthy of Sweeney. When I worked with Simpson in southern Africa, he was brave to the point of being foolhardy. He would directly challenge the thugs who posed as policemen in Soweto, when more cautious reporters (like me) would be looking for a way to get the hell out.

There was nowhere he would not go, nothing he would not do. I have seen him intervene - at great risk to himself - to try to protect a man being beaten. And staying in Belgrade was not the act of a coward. When your own country is bombing the place, you are seen as one of the enemy. He had no way of knowing what would happen to him. By all means let Sweeney argue with Simpson's analysis of the Kosovo war, but he should not question his courage. John Sweeney is a fine reporter and a brave man. But so is John Simpson.

And so to my new book: I'm fed up with everyone telling me how smart I have been to capitalise on the crisis in agriculture. Not so. When I first had the idea, years ago, I hoped to break some new ground by challenging the notion of "cheap" food. The true costs of intensive agriculture are enormous. We pay to subsidise grain we don't need. We even pay farmers not to grow it. We pay other farmers to keep too many sheep. We pay the water companies to clean chemicals out of the water. We pay the social costs of destroying rural communities. And we pay when things go catastrophically wrong: the bill for BSE is in the billions and still rising. We don't know the real cost to our health of chemical residues in food, because so little research has been done. Who is there to pay for it? Hardly the agrochemical companies. But what was once a radical analysis is now almost an orthodoxy.

I have called the book The Great Food Gamble because that is what we have been doing for 50 years: gambling that it is possible to force the land and animals to produce ever more food, without paying a price in the long run. I hope I have proved that we must stop it. The gamble has not paid off.