In all the polishing of Cherie Blair's book, The Goldfish Bowl: Married to the Prime Minister, that's been going on lately, one thing seems to have slipped past. Her book on prime ministers' wives was originally planned, we are told, as a "maternity leave project".

Let's just say that again - "maternity leave project".

Now, I find this notion offensive on several levels (being a practised multi-tasker and working mother I can do that - I could be offended on several levels, hold down a demanding day job, have four children, write books and be married to a world leader all at the same time without batting a curled eyelash).

I am grammatically offended. Maternity leave already has a project - indeed its raison d'être is specifically a project - the one whose name it bears: yeah, maternity. It is a contradiction in terms to have a maternity leave project which is not a baby. (This isn't the first time books and babies have been confused - Candia McWilliam famously observed that for every baby you lose three novels.)

Second, as a mother. This kind of laxity - suggesting that it is possible to do other things while in charge of a newborn - reflects badly on the rest of us, who find our time fully occupied with bleeding, feeding, picking at the stitches, changing nappies, laundry, bathing (the baby, not ourselves, silly), singing, washing up, mashing bananas, mopping up, falling asleep while driving and so on.

Top three on my list of putative maternity leave projects would have been half an hour's kip, time to wash my hair and a glass of wine. And I had just the one child and no live-in father to attend to, let alone one who's working all hours ruining the UK's international reputation and chumming up with the world's worst leaders.

Cherie, you have a bucketload of kids! Maternity leave is for your family - we must talk to them now, or they'll end up in Lesotho being nice to Aids babies in our memory because they haven't seen us for so long they'll think we must be dead.

Third, it's moonlighting. We're paid maternity leave so we can mind our babies and bond with them and live in a future full of well-adjusted happy people, not the poor, depressed, neglected, self-harming, unemployable drug-addict teens we read about. Not to skive off and do a few extra shifts at Woolies.

Fourth, and most of all, I mind as a writer. I've managed to get over the fact that the editor of this paper has written a book, because it is very short and for children, but Mrs Blair's book, though co-written, is not short and looks as if it's meant to be taken seriously.

This is very, very bad. Books are not things you knock out between other engagements. Our day job, our raison d'être, is not your extra-curricular activity. It is because high-profile people do this over-achieving "rustle it up while you're waiting for the taxi" kind of publication that decent, honest, hard-working writers like me and hundreds of others have to put up with comments such as, "Oh, and do you make a living from that?" (Why? Do I look destitute? The last to say that to me was a doctor, so I asked him if he had any patients.) And, "Really! I was going to write a book but I just don't have time." (Of course you don't. It's not your job - and you're not Cherie Blair. Or Hillary Clinton. Or Naomi Campbell. Or Alan Rusbridger.)

It happens with other creative work as well. My boyfriend was seeing a physiotherapist. "What do you do for a living?" she asked, filling in her form. He explained he was a film and TV composer. "Lovely!' she said. "Any other hobbies?"

Not many supermodels and prime ministers' wives knock out film scores as their "maternity leave project". It is generally accepted that you need to know how to write music to write music. But books - shoot, anyone with a spellcheck and a nanny can do it. Go on, you can get one in this weekend.