‘It’s the boys. I can’t have people sniggering behind their back. But I had to tell someone. Someone who wouldn’t judge me. Or Clare. There was only you.’

Well, that’s a bond. Of sorts. Welcome to the North London fuck-ups club. Official membership, two.

‘I am grateful you told me. Seriously.’ There’s a rueful snort. Which is a relief. ‘There’s a lot for me to think about too,’ I say.

A pause. ‘I guessed you’d somehow end up making this about you.’ He sighs. ‘See you, Gil.’

I’ve been walking angry, unthinking strides. I clock my surroundings. I’ve reached the north-east corner of Parliament Square. The familiar silhouette of Big Ben’s tower looms, solid and eternal. I can’t face the Burma Road. I know who I need to see.

*

I am in my nothing box: my psychological state where there is nothing definable, nothing conscious, absolutely nothing happening in my head. This ability to blank my mind, to go into a sort of short-term hibernation, like a computer entering sleep mode, is what keeps me sane. Since Clare’s death I’ve been more or less always on and if I keep it up much longer I’ll overload. It’s bliss to be back in this imaginary flotation tank.

It’s 9 p.m. and I’m on my king-sized bed, with the senior policy adviser to the Leader of the Opposition lying naked beside me. Marilyn does not have a mind-blank mode. She’s been cuddled against me for about five minutes and most of that was spent fiddling with a knot in her necklace chain. Now she sits up and pulls a packet of Marlboro Lights out of her battered brown leather rucksack.

I snap out of the trance. ‘Do you really have to?’

‘I thought you were asleep.’

‘It’ll stink up the bedroom.’

She just laughs. She knows she’ll get her way. I sigh, and pass her the Spurs mug on my bedside table to use as an ashtray.

She lights up, takes a drag and blows out a long stream of smoke. ‘Your sister. Jesus, Gil. And you’ve really no idea who the father could be?’

I wince. My promise to Charles has not survived more than a few hours. I kid myself there’s no one Marilyn would possibly wish to tell, as if one woman in politics would never want to gossip about another who was a rising star in Whitehall.

‘You’ve got to promise you’ll keep this to yourself. I can barely imagine the humiliation my brother-in-law would feel. And I want to protect my nephews.’ It’s absurd that I am asking her to show a duty of care to the boys when I’ve so casually betrayed them by gushing to her.