After school, Tanvi intercepts me at the school gates and tries to offer me a lift. Even though she eventually accepts my refusal, I still feel uneasy as I walk home, glancing over my shoulder every few steps.

I’m turning into Arcadia Avenue, when my phone buzzes. My heart does a little lift when I see Noah’s name on the screen. It’s only a short message – hello and how was school – but I don’t care, quickly tapping out a reply. We message back and forth for the next few minutes. Our conversation is nothing special – notes on our respective days – but it feels significant somehow, like the beginning of something real.

I’m in the kitchen adding dried pasta to a saucepan of boiling water when Bonnie staggers through the back door wearing a tie-dyed kaftan and a pair of jewel encrusted flip-flops, a floppy straw hat on her head. Her face is flushed and her eyes are shining. Combined with the bulging carrier bags looped over her wrists, this means just one thing – she’s been shopping. And just like that, my good mood evaporates.

‘Oh, hello,’ she says, dumping the bags on the already heaped kitchen table.

I wait for her to ask me how my first day back went, but despite the fact I’m wearing my school uniform, she’s clearly forgotten.

‘What’s in the bags, Bonnie?’ I ask instead, trying my hardest to keep my voice steady.

‘Oh, just a few groceries,’ Bonnie says vaguely, running her fingers through her hair. ‘Lidl have some brilliant offers on at the moment.’

I peer in one of the bags. ‘But we already have peas,’ I say, noting the half dozen tins. ‘And rice. And since when do we use that much soy sauce? There are like ten bottles here.’

‘I like to dip my prawn crackers from the Chinese in it,’ Bonnie says, pouting.

‘So buy one bottle.’

‘It was buy one get one half price.’

‘So buy two bottles.’

‘And then run out and have to go back and buy them at full price?’ Bonnie tuts and wags her finger. ‘I thought you were supposed to be clever, Ro Snow.’

According to whom exactly? I always give Bonnie my school reports to read, but I doubt she gives them much attention. If she did, she’d know I’m totally average in every single subject – middle set across the board.

I spot a packet of cigarettes nestled on top of at least six tins of fruit cocktail. ‘I thought you were giving up,’ I say, holding them up.

‘I’m cutting down,’ Bonnie replies, plucking them from my hands and clutching them to her chest. ‘This pack will probably last me all month.’

Yeah, right. I’ve emptied her ashtray at least five times in the past week alone.

I move on to the next bag. It’s full of greetings cards. Annoyance stirs deep inside me. I take out a handful and leaf through them – ‘Congratulations On Passing Your Driving Test!’ and ‘I’m Sorry For Your Loss’ and ‘Happy Hanukkah!’

‘Who are these for this time, Bonnie?’ I ask. It’s getting harder and harder to keep calm.

‘Just people,’ Bonnie says vaguely, picking up a bottle of soy sauce and studying the label.

‘What people?’

Bonnie and I don’t know people. Bonnie isn’t in touch with any of her family, and apart from her singer friends – women who enter and exit her life like they’re riding a carousel – she has no other significant relationships I’m aware of.

‘I don’t know yet,’ Bonnie says.

‘So why did you buy them?’

‘Because you never know when they might come in handy.’

I turn one of the cards over. ‘This one cost three pounds seventy-five!’

‘Oh, did it?’ Bonnie says. ‘It must be all the embellishment. Isn’t it pretty?’

I wouldn’t mind so much if Bonnie sent the cards, or even just put them away carefully. But she doesn’t. She just dumps them wherever she feels like it, just like she randomly dumps everything she brings into this house, regardless of its value.

I look at the rest of the price tags, adding up as I go. ‘You’ve spent over forty pounds on cards, Bonnie.’

‘I told you, they’re an investment,’ she says, snatching them from my hands and stuffing them back in the bag.

‘Did you pay for all of this with cash or card?’

‘Card. Why?’

‘The water bill comes out of the account on Friday. This lot is going to send us over our overdraft limit.’

God, I hate the way I sound right now. Like a middle-aged nag. Everything is the wrong way round. I’m 14. I should be the one being told off for wasting money; it should be Bonnie worrying about all this stuff, not me. My chest burns with familiar resentment.

‘Well, there’s no point it getting in a tizz over it, is there?’ Bonnie says cheerfully. ‘It’s done now. Besides, I’ve got three gigs at the weekend – Friday, Saturday and Sunday. Pip who, eh? Come this time next week, we’ll be back on track, you’ll see. Now, are we done here, because I’m dying for a wee.’

She doesn’t wait for an answer, dropping the bag of cards on the floor and humming as she disappears into the hallway.

My fists tighten. I want to scream, to take every one of those soy sauce bottles and smash them against the concrete paving slabs outside.

But I know I won’t. I can’t. Because I’d be the one who’d have to clean it up, so what would be the point in that?

The boiling water hisses as it foams over the side of the saucepan. I swear under my breath and reduce the heat.

I can hear Bonnie singing ‘Son of a Preacher Man’ at the top of her voice – not a care in the world. I shut the door to the hallway to block it out and reach into the back pocket of my jeans for my mobile.

After listening to three separate automated menus and successfully passing through security, I finally make it through to a human being.

‘Hello,’ I say in my very best grown-up voice. ‘My name is Bonnie Snow. I’d like to extend my overdraft please.’