‘You’ve got the likeability factor, Kassidy,’ says Dad.

‘The what?’ says Raff.

‘It’s what Simon says. Likeability. It’s even more important that having a good voice – and Kassidy has got it.’

My brother comes over to me.

‘This Kassidy?’ he says. ‘Err, she only has two friends. How is she likeable?’

He’s right, but I’d still like to hit him.

‘Raff, if you’ve got nothing sensible to contribute … ‘ Dad wags his remote with a stern look on his face, and Raff takes a seat with his hands in a prayer position as if we’ve just been doing judo, an impish grin on his face.

Mum is doing her nervous throat-clearing thing. As usual, she’s choosing to ignore what’s going on. Well, it’s not as if Dad’s On The Up mood affects her.

Dad un-mutes the telly, and he and Raff chew pizza and grin at each other like happy pigs eating from a trough. My dad is too dense to realise that Raff is laughing at him, not with him. Raff knows that when Dad is occupied with a grand plan for me, the spotlight isn’t going anywhere near him for a long time, and that can only mean: kerching!

Mum pats a space next to her to beckon me in.

‘Come on, it’s just the ads now,’ she says. But as I sink into fake leather I see I’ve been duped.

‘If YOU want to audition for the next series of The X Factor, here’s what you need to know.’

My dad knees his way towards the television with half a slice of pizza in his mouth and a pad and pen in his hands.

‘Band members and solo artists must be aged sixteen or over to enter—’

‘Ha! See?’ My voice is so excited I sound like I’ve inhaled a helium balloon. ‘Aged sixteen, aged SIXTEEN, did you hear?’ Bottom-bouncing on the sofa is probably not a good look but I’m very, very happy. It’s over! I’m saved!

But wait, why is Dad shaking his head, revealing a smug smile oozing with pizza?

‘Dad? What is it?’ He looks like a demonic four-year-old whose parents are about to discover that he’s crayoned all over the Plasma telly.

‘Passport,’ he says, into his chest, trying to hide his grin. ‘I know a bloke who knows a bloke who…’

‘You can’t be serious! So now you’re turning me into a criminal? No way.’

‘Yes way.’

How can I debate reasonably with a thirty-nine-year-old who still uses the no-way / yes-way tactic? I need new ideas, and fast.

‘Dad, think about it – people always get found out when they lie about their age on these shows. Why not just wait a year or two until I’m old enough?’ (As in, old enough to leave home, change my identity and live peacefully on a small island earning a living making useful things out of coconut shells – anything but this!) ‘Plus, Dad, look at me – I don’t look sixteen.’

Raff comes over, snarling in the direction of my chest. ‘S’true. She’s got no boobs, look.’

I gasp and cross my arms over my chest, and try unsuccessfully to punch him in the head with my elbow. Dad roars: ‘Rafferty! Stop looking at your sister and go have another slice of pizza.’

I hate to agree with my brother – on anything – but he has a point. Plus I know how much my dad hates talking about things like “boobs”. I might be able to embarrass him into submission.

‘Raff’s right, Dad. They’re flatter than fried eggs.’

‘Enough,’ he says. ‘No more talk of…them. I’ve got to think.’

‘You’ve done enough thinking,’ I mumble. He takes another huge bite of pizza.

‘I’ve got it,’ I think he says, though it’s slightly muffled until he swallows. ‘We’ll say you’ve been poorly.’

‘Paul!’ Mum hardly ever ‘Pauls’ him; at least it’s not just me who thinks he’s finally lost his one remaining marble.

‘That’s not getting it,’ I say. ‘That’s the opposite of getting it. I’m not “poorly”, Dad, I’m just fifteen. And tone-deaf. Game over. The End. Let’s just turn it off and play Pictionary.’ (You know things are desperate in this house when someone volunteers to play a competitive game with Dad in the room. Especially Pictionary. Especially when he’s like this. We could end up with extravagant doodles all over the wallpaper, like Rolf Harris on a caffeine high.)

‘This is your twist,’ he says. ‘Everyone needs a twist on this show – a gimmick, something that people will remember, maybe even feel sorry for.’ Dad gets up and paces the room as if he’s solving a crime. As a matter of fact, this is a crime, with several charges: passport fraud, entering a competition under false pretences and child cruelty, for starters. But Dad will never point the finger at himself.

‘Dad, people will remember me for being rubbish. You know this – you make me enter karaoke every year on holiday and I never, ever fail to suck!’

He is chewing pizza so quickly it’s made him profoundly deaf. I try again.

‘Anyway, saying I’m ill isn’t a twist, it’s a lie.’

‘It’s terrible,’ says Mum, but much too quietly to have any effect.

‘It’s brilliant! Your likeability and my sales skills … come on, you lot, you know I could sell lard to Victoria Beckham! I’m on the up!!’

Affirmative. He’s in another world. And I’m in hell. Suddenly he jabs his pepperoni slice in my direction.

‘Sing us something, Kassidy. Come on, just a few bars.’ He tries to get me up and over to the mantelpiece using bare enthusiasm, as if I’m some half-witted Andrex puppy. ‘She’s good, Grace, she’s really improved.’ My mum smiles at him. Don’t smile at him, that’ll just encourage him! ‘This is it,’ he says, clenching his fist as if he’s just discovered a way of turning house dust into gold.

He’s too far gone for me to argue. It could make him worse; he’s not like other people. I feel awful saying that. It’s not that I’ve completely forgotten all the ways that he can be amazing like other dads don’t seem to be – like the spur-of-the-moment holiday to Florida, or the day he got his ear pierced with me because I was scared to do it on my own – but lately it feels like he needs Handle With Care tattooed on his forehead.

I need help, and I’m not going to get it in this room. If I protest any more he’ll list every sales job he’s ever had and every dream sale he made, starting with the Famous Bag Of Manky Cooking Apples (circa. 1979) and not forgetting the time he shifted three washing machines to the same person (well, I’d buy three washing machines just to make him GO AWAY!). Or Worse, and believe me, there is a Worse. It’s not the kind of Worse you can get locked up for, but it’s the kind you don’t invite to parties. It’s the kind nobody really talks about.

I’ve got to get out of here.

‘Actually, Dad, I’ve got a bit of a tickle in my throat. Better save my voice, don’t you think?’

From the look on his face you’d think I said terminal, not tickle. He clamps my shoulders meaningfully between his hands and looks into my eyes. Then he runs from the room and the rest of us wait in limbo. When he returns it is with a glass of cloudy liquid, which he stirs frantically, not noticing the small spills on his trainers.

‘Here, drink this.’

‘What is it?’

‘Salt water. The professionals use it.’

I look at Raff, who cannot conceal his joy.

‘That’s right,’ Raff says. ‘Britney uses it.’

Dad snatches the glass from my hand.

‘But she’s ruined herself,’ he says to Raff. ‘Two young children and all that rehab for that, umm, whatever it is she’s got.’ We all go deathly silent, and there’s only the sound of the spoon clinking around the glass. He looks at the drink as if salt water were directly responsible for Britney’s downfall. Raff nods and says:

‘True, but I also heard that Kylie drinks it.’

‘Really?’ Dad’s face lights up again. He stops stirring and passes the drink back. The temptation to throw it over my brother is huge – he doesn’t have to put up with any of this unwanted attention and all he can do is gloat – but I’ve got to play the long game here. This is no time for rash actions.

I cough a little and put my hand to my throat as if I’m in pain. It’s lame, but it works.

‘I’d better have this upstairs and then get some rest.’

‘Yes, yes, off you go, Kassidy.’ As I’m walking away he’s saying, ‘Good name for a pop star, isn’t it?’ And Raff is agreeing and Mum is silent, of course.

I trudge up to my refuge with a glass of spew. Dad’s still bouncing around and I can barely put one foot in front of the other. How can someone being that happy make me feel this bad? But here’s the irony. This is how we all prefer Dad – by a whisker – because when he’s not acting like this he’s being something completely different; and you really, really don’t want to know.