I am developing a work-related illness, a sort of RSI of the brain with complications. It all began five years ago, when I started reading several newspapers every day and listening to news bulletins "on the hour, every hour".

It was in the autumn of 2000 that my husband first drew attention to the symptoms of my illness. Pictures of George W Bush were on most front pages. My daughter was spooning cereal delicately on to the floor.

"Oh, fuck off!" I yelled. Two heads snapped up guiltily. Matching eyes watched me in dismay.

"Should you be talking like that to a baby?" he asked cautiously.

"Not you two," I snapped. "HIM!"

I was waving the Mirror around and stabbing George W's face with a toast soldier.

That was stage one; overexposure to hypocrisy has resulted in my losing the ability to form a coherent argument against the subject of my loathing and adopting the vocabulary of The Osbournes. I just curse in every direction.

It appears that I have now entered stage two, a worrying development that is affecting my ability to broadcast live in front of the public without causing offence. Take the episode at Sky News a couple of weeks ago. It was 11.30pm, and I was in to do the newspaper review. The Guardian's front-page story was about tax; a dry husk of news not usually my bag at that hour of night. But the writing was pure comment and demanded an emotional response.

"Imagine a gamekeeper sending a letter to the local poachers, telling them that, in future, he would trust them not to shoot the pheasants,"it began. "Now look at the Inland Revenue's recent Hartnett Review . . . " The article went on to describe how multinational corporations will not be as rigorously investigated as the rest of us. In fact, they have been invited to suggest the ways in which they would like to be reviewed.

On-air, the presenters introduced me and I had to clench my fists under the desk to stop myself shouting: "Shit, shit, damn, bugger, bastards!" I managed to outline the basics of the story calmly. Then I panted: "Can we move on now? I'm not sure I can say any more without swearing."

It's the combination of journalism and politics that's to blame for my deterioration. And the other night, I may even have slandered a newspaper editor on-air. A tabloid had a particularly noxious front page on "asylum-seekers". Their crime this time? To be given the chance to learn English - for free. The conclusion drawn was along the lines of: "Who do these poncing foreigners think they are?" I reviewed the piece with care, before linking seamlessly to an article on exotic creatures roaming the streets and sewers of Germany with: "The owner of that paper is So-and-so, and talking of slimy lizards . . . "

Once upon a time, it was only diarists who could reduce me to such a level of fury. This week, one rang me up to "congratulate" me on some very private news.

"Hi Lauren, wonderful news about the baby."

"What baby?"

"Your baby?"

"My daughter?"

"No, the new one, the one that's on the way . . . "

"How did you . . . ? Oh, never mind."

All he got for revealing, in a particularly unfortunate week, that a friend had broken a personal confidence was a weary sigh and a promise that we'd "do lunch soon".

Roll on stage three of my political Tourette's syndrome: the one that Polly Toynbee suffers from - and which involves dowsing those you dislike with cheap wine instead of abuse.