‘I know. I know. I know.’ She puffs out an unhappy breath. ‘I ended up phoning Zak and he came down to Bath to hang out with me.’ My sister tries to shrug off her dis appointment, but I can see the pain in her eyes. ‘All’s well that ends well.’

‘Why didn’t you call me?’

‘Of course, I called you. But you were up a mountain somewhere without a phone signal.’

I’d forgotten about that. Or maybe I’d just decided to blank it as an unpleasant experience. But then, it wasn’t unpleasant – not the walking bit: I loved it. Only the falling-out-with-the-husband bit put a damper on it. ‘You seem to be spending a lot of time with Zak.’

‘He’s cool,’ Lauren says. ‘A lot of fun.’

‘And available?’

‘Don’t go there,’ Lauren warns.

Then Chelsea arrives and I can’t interrogate her any further. Oh, God. Lauren is right. Our big sister is looking beautiful and pristine and already my inadequacy levels are rising.

‘Hello, girls,’ she says, and then kisses us both on the cheek. Chelsea isn’t an enthusiastic kisser. Her lips are cool, dry and I bet she hasn’t left a lipstick mark either.

Chelsea is wearing a baby-pink cashmere sweater and black wool trousers and looks a million dollars. None of it, I know, will have come from George at Asda. The shoes, I suspect, are Prada, Jimmy Choo or something. The handbag is one of those over-size ones that celebrities use.

I pull out a chair for my big sister and generally fuss round her, earning myself a glare from Lauren in the process. My twin looks miserable. Taking Chelsea’s order, I scuttle off to the counter and get it for her.

‘One skinny latte,’ I say, when I bring it back. What else?

Lauren – whom I’ve persuaded to eat – puts down her slab of Rocky Road and gives me another pointed and black look.

‘It’s great to see you both,’ Chelsea says. ‘We don’t do this often enough. The three of us, I mean.’ A tacit acknowledgement that Lauren and I get together more often without her.

‘We should,’ I gush. ‘Now that you’re back for a while. It is nice to be in your own home again?’

‘Yes.’ Again, I’m sure I see a shadow cross her face. Then my sister sweeps back her luxuriant hair and smiles and I’m convinced that I imagined it.

‘How’s the boyfriend?’ Chelsea asks.

‘Great,’ Lauren takes up the gushing. ‘We’ve just had a fabulous weekend in Bath together.’

Chelsea’s lips tighten almost imperceptibly. Lauren’s eyes challenge me to spill the beans on her lie.

‘Lovely,’ Chelsea says and then turns to me. ‘What have you been up to, Annie?’