Despite Tallulah’s warm greeting, Dinah isn’t impressed with her. Once she’s out of earshot, Dinah says, ‘Look at her skin – sun damage,’ she says, leaning her head towards mine and pointing as if I don’t know who she’s talking about. ‘She looks her age. Her blonde hair is greying and her upper arms are losing tone – why’s she wearing short sleeves? Why doesn’t she try to appear younger?’

‘Personally, I’ve always admired women who let their hair grow grey,’ I say.

Dinah has a different opinion. ‘You don’t see me with white hairs,’ she says disapprovingly.

‘That’s because you colour it,’ I point out.

Dinah’s indignant. ‘Who says? I suppose it’s a good look if you can keep your nerve, but who would want to?’

Dinah has the open curiosity of a child when it comes to people. She’s distracted by a woman in her seventies with an asymmetric bob, a geometric structured black-and-white jacket, white plus fours and black-and-white zigzag socks, and black brogues. ‘Stylish,’ she says.

A couple of good-looking men come to sit a couple of seats down from us. I realise that they’re fussing over a white Yorkshire terrier and I get anxious and uneasy.

‘Let’s move further back,’ I suggest nervously. I won’t be able to relax while the dog is there.

‘Why?’ Dinah looks up from her auction catalogue and turns around to look at the room, which is filling up. ‘No,’ she says, ‘I like it here.’

‘Swap seats, then?’

‘What’s wrong with yours?’ she asks suspiciously.

‘The dog.’

‘That thing?’ She looks at it over her spectacles. ‘What’s wrong with it?’

I could tell her I’m afraid of dogs because of their unpredictability, their jumpiness, the barking that’s always loud and startling. I’m afraid of them because dog lovers always say dogs can sense fear and that makes me fearful. I’m afraid because dog lovers always tell me their dog just wants to play, even though it’s straining at the leash and making a rumbling noise in its throat. And I know about the prey reflex that means that when the fear gets too much to stand and you try to get away, dogs are hardwired to come after you. I don’t want to tell her, because she won’t understand. People don’t.

But Dinah has a fine-tuned sensitivity to mood. She shrugs and without asking any more questions, she gets up and changes seats with me.

The two men fuss over the white Yorkshire terrier until it farts with happiness. The fart spreads slowly and hangs in the air, taking its time to dissipate.

‘Disgusting!’ Dinah says loudly, fanning her catalogue furiously while I pretend not to notice. ‘That’s why you wanted to change places?’ Someone else catches her eye.