‘One never thinks about it, of course, but there must be loads of married couples who’ve been in my shoes. Everyone imagines that the wife wins, gets her way, on the grounds that, when a couple has adored children already, it is, presumably, unthinkable to terminate the life of a future sibling. Well, you know what? It isn’t. It happens. To thousands of married women every year. Tens of thousands, maybe. It just has to me, so I know.’

I place my hand briefly on her leg, then back on the wheel, as if what she is saying is so profound that any reply of mine would only diminish it.

‘If you think about it, one of them has to win, but then one of them has to lose, too. It’s just that usually the woman wins, and the man is left in the position of saying, “It’s the best thing we ever did, of course I was terribly unkeen at the time, I know I was, darling’” – Mimi adopts the plummy, jovial tone of the English public-school father for this bit – ‘ “but once he arrived, how could I ever regret Archie, eh? He’s the love of my life!” And then the wife looks smug, as if he should be thanking her for holding the line and overruling him during the bitter row over whether to have or not to have the baby. Rose, husbands and wives go head to head on this all the time, and I lost.’

‘You didn’t lose as such, Mimi,’ I say. ‘I know it’s horrible, but you have to think of Ralph, and the Whole Family Unit.’

‘I did lose,’ Mimi intones, bleakly. ‘It was my turn to lose. Sometimes, you lose.’

I knew what Mimi was talking about here, but I didn’t pick up the thread. Her fling with some single sleazy billionaire who bought a house on her communal garden. Si someone. She had sex with him twice. Once in a hotel – the Grove, I think, that hotel for WAGS with a golf course, near the Watford Gap – and once on his stairs in Lonsdale Gardens, an episode that she described as ‘a stairfucking’, which she described as ‘jolly bad for the back but a lot more fun than starfucking, which is all that most people do with any enthusiasm in Notting Hill’.

‘But that’s the worst bit!’ says Mimi. ‘The children. I was doing a good job of holding it together, but then Cas suddenly said, in the kitchen, when something came on the radio about the England cricket team, “If only I had a little brother” – he’s always longed to have someone to do nets with – “If only I had a little brother, I could teach him how to play cricket.” I thought I’d… black out! I had to rush to the larder.’

‘The larder?’