‘He’s married to Mandy,’ says Jeremy, stating the obvious.

‘Come on, you know what I mean. Is Kendall the only Tory minister without a bit on the side?’

It’s a joke – but Jeremy looks horrified. ‘Well, if he has, he certainly wouldn’t tell me.’

I’m struck by Jeremy’s squeamishness. ‘Obviously he would hide it from Lady Mandy,’ I say. ‘Though you’d be surprised how many of these posh people have “open” marriages. I imagine his secretary would know. A decent secretary knows everything.’

Jeremy sticks his hands in his pockets and stares at the ground. ‘I don’t think there’s anything like that going on.’

‘Are you sure. No telltale signs? Sudden departures from the office that aren’t in the diary? A decision to walk somewhere rather than take the ministerial car? Has there been tittle-tattle from the official drivers about being parked outside a residential address for a couple of hours?’

Jeremy is now staring vacantly at the lake. I don’t know what to make of it. Ringer is rarely wrong, but if Kendall indulged in extra-curricular bonking, surely there’d be rumours at the office?

But before I can press him, his head snaps to the right. ‘What’s that over there?’

‘Where?’

‘Behind the willow. Is that a camera lens?’

I scan the bank on the other side of the pond. About a hundred yards away I can make out a point of reflective light. It could be a telephoto lens, or binoculars.

‘Probably a birdwatcher,’ I say.

‘You’re right. I’m on edge. Meeting like this . . .’ The sun is now fully out, but Jeremy has kept his hood up the whole time. ‘I’d better get back. Would you mind if we split up?’

‘Of course not.’ I too feel the strain. Being with him and his brain full of plots reinforces my anxiety. ‘But about Kendall, and his love life . . .’

‘There’s nothing. I am sure there’s nothing there. Got to get back before they miss me.’

He digs his hands into his pockets and strides purposefully towards Horse Guards.

I cross the bridge again and turn left on the far side of the lake, towards the place where Jeremy thought he saw the snapper. Of course there’s no one there, but I linger, trying to make sense of what I heard.

Kendall’s finances feel like a blind alley. His private life is another matter, but if there’s anything doing there, I won’t find it from Jeremy. He’s a choirboy. Kendall could have been shagging his secretary sideways on the dispatch box in the Commons and Jeremy wouldn’t have noticed.