‘Oh, come on. You’re a nurse. Don’t be so prudish. I bet there’s a vibrator or two lurking in your bedside cabinet.’

‘If there is, I’m certainly not telling my sister about it,’ I say with a laugh as I pull open the door of the enormous shiny SUV that Greg replaces pretty much every year with a swankier model. He says it’s because his car has to reflect his sales success and to make people take him more seriously, but I suspect he’s secretly compensating for something.

‘Hello, Isaac,’ I say to my nephew, who’s securely strapped into the kind of child seat that wouldn’t look out of place in a racing car. It has side, hip and head bolsters, as well as more straps than seem necessary. When I initially asked about it, Tash confided that she’d have been perfectly happy with a normal one, but Greg had insisted that nothing but the top of the range was good enough for the fruit of his loins and, after meticulous research, bought a seat so large and heavy that Tash can’t actually lift it into the car on her own.

‘’Lo, Auntie Tilly,’ Isaac replies, giving me the briefest of nods before returning his attention to the screen built into the headrest in front of him.

‘What are you watching?’ I ask as I clamber in next to him and do up my seat belt.

‘Thomas,’ he says matter-of-factly, as if that’s all the explanation required.

‘Isaac is into Thomas the Tank Engine at the moment,’ Tash explains as Greg noses the car out on to the road.

‘Bit vintage, isn’t it?’

‘Yes, but Greg has fond memories from his own childhood. It’s a bonding thing, apparently.’

‘I see.’ I turn back to Isaac, trying to dredge up my very vague memories of the children’s TV series. ‘Which engine is your favourite?’

‘Gordon,’ Isaac tells me as if it should be obvious.

‘Really? Why?’

‘’Cos he’s the biggest and the fastest, silly.’

‘Isaac,’ Tash warns him. ‘Don’t speak like that to your aunt.’

Isaac looks confused. ‘Why shouldn’t I call her silly? It was a silly question.’

‘Because it’s rude.’

‘I think,’ Isaac declares in the kind of defiant tone that makes me suspect this conversation isn’t going to end well, ‘all grown-ups are silly.’

‘Enough, Isaac,’ Greg suddenly bellows from the front seat, making us all jump. ‘Say sorry.’

I can practically hear the cogs turning in Isaac’s mind as he tries to decide whether to push this further or concede defeat, and I’m relieved when he evidently decides to take the second path.

‘Sorry,’ he mumbles before turning his attention back to the screen.

‘How’s work, Greg?’ I ask once it’s become clear that Isaac is fully immersed in the story once more.