Chequers: mid-September: 'To-nee, can you stop playing that video game with Euan for just a moment? I've got a little domestic problem I need to discuss with you. That's right, Euan. Go outside and play football with the policeman. I'm sure he can put down his machine gun for a few minutes.'

'Really, Cherie, you can't call Worms a mere video game. It's a team-based strategy package in which I am showing Euan how to destroy the Conservatives by cornering them as extremists. I was about to zap William Hague with my bazooka when you came into the study without knocking. I could have been reading secret documents.'

'Men, they're all children. I can only hope that, were we to have another child, it would be a sister for Kathryn. Which is actually what I wanted to talk to you about.

'Do you remember that moonlight dinner we had with Tom and Molly Savoir-Faire in Gascony last month? Around the 25th, as I recall. A perfect summer's evening, it was the night the chateau's fax machine unexpectedly ran out of paper so that Downing Street couldn't send the overnight files. And Euan's lap-top mysteriously went on the blink, so you couldn't relax by playing Worms .'

'Really, Cherie, I'm not sure where this is getting us.'

'I think I'm pregnant.'

'Good God, I am completely, totally 100 per cent stunned, but almost immediately delighted as well.

Darling, it's terrific news. Big kiss. When are you due exactly? Alastair, unless Cherie has got her sums wrong we can make this work for us in the May local elections and also use it against Ken Livingstone. He has no kids at all, you know, unless you believe the tabloids.'

'But Tony, this has serious implications for us as a family. We need more room. Gordon may have to give up his flat next door. And there are policy implications. As prospective parents we must set a good example, better than my old dad who did a runner when I was a tot, for instance. Broken homes, too many unplanned pregnancies, higher infant mortality rates than the EU average. There is an opportunity here.'

'Yes, I see. I hadn't thought of that. Alastair, cancel the press release. You mean we could make it an educational experience targeted at the young, and get some funds from Gordon's training budget to raise awareness of pre-natal good practice? We could even find more money for NHS midwifery, to sustain pioneering schemes under threat from cuts in some health authorities, including Essex. It would be a boost to Dobbo or whoever I decide to appoint as health secretary when Frank quits to run for London mayor in a few weeks' time.'

'We'll use an NHS hospital, of course. And you'll be present at the birth as you were for Euan, Nicky and Kathryn - who was, you may recall, delivered by Caesarean section. We can show people how a healthy, modern, career woman can take a late pregnancy in her stride. And you can avail yourself of the right to unpaid paternity leave as prescribed by the EU's social chapter, which you so sensibly signed.'

'It's a very busy month, May, darling. There's the local elections and, of course, the cup final. I need time to prepare for that. You don't suppose you could have the baby here at Chequers, a water birth, perhaps? The pool will be quite warm by May.'

'Lovely idea, Tone, but I'd be afraid that Alastair would let The Sun install a photographer up a tree in the grounds. He's trying to be nice to them to boost your campaign for the euro. Incidentally, I've been studying the figures. Did you know that one-fifth of women between 16 and 49 who require family planning services went to clinics in 1998? That's 1.2 million by the way, plus 80,000 men. Only 80,000! I ask you, aren't they hopeless?'

'Why yes, young Milburn was telling me the other day that the peak age for clinic attendance is 16 to 19, which ought to be encouraging considering our high teenage pregnancy rate. Oral contraceptives were preferred by 42 per cent, against 37 per cent still favouring condoms, I recall him saying. He certainly keeps up on health matters for a Treasury minister, does Alan.

Perhaps I'll give him Frank's job instead of Mo. But won't people say our baby is unplanned?'

'Unplanned? You're so sweet.'