I creep upstairs and stand outside Maisie’s bedroom door.

I can’t hear the television, or music. The room seems deathly quiet.

I open the door very slowly and see that, as I suspected, she has fallen asleep, fully clothed, on the bed.

The light from the landing floods the room and illuminates her face. Her skin is pale, almost translucent. Dark curls lie fanned on the white pillow beneath her head, and her eyes are closed. I watch as her eyelids flutter like butterfly wings caught in a light breeze.

I draw comfort from this. A sign that she is still in there somewhere, dreaming of happier times we have shared, perhaps. Something more than a narrow chest rising and falling with laboured breaths.

Her body looks so small now, too small to properly match her head. Too frail to do all the things that she used to do now that food has become her enemy.

Food. Always there for all of us; a pleasure, a necessity… at times in my own life, a terrible temptation I have had to fight.

After our visit to Dr Yesufu, I became more aware. I watched how Maisie had become skilled at carefully deconstructing each meal I served so that it looked as if she’d eaten some of it when in actual fact barely a morsel had passed her lips.

Her method became recognisable.

The way she’d spear a clutch of green beans on her fork and flatten her new potatoes. Shunt a chunk of salmon under a pile of untouched dark green leafy vegetables.

An impressively inventive and successful way to decrease the volume of food without actually swallowing it.

But I too have become skilled – in covertly watching her. She has never been fat but was once slightly plump around her middle in a perfectly healthy pre-teen way, with apple cheeks that shone when she laughed.

I’ve learned to refrain from commenting when the waistband of her smallest jeans bags looser still. When her favourite pink glittery belt can’t be pulled any tighter yet is obviously still too big.

After the doctor’s advice, I bought her a whole new set of school uniform without comment. Not because she’d outgrown the old one, but because it hung off her now slender frame.

It’s all I can do.

She won’t talk to me, you see, so I began to gather evidence, adding my daily observations to a heartbreaking, password-protected spreadsheet on my laptop.

Dr Yesufu said it might well just be a phase.

His advice reflected the professional opinions of the numerous eating disorder websites I researched online.

Don’t watch her eat.

Don’t comment on her appetite.

Don’t talk about food or the profusion of perfectly photoshopped celebrity bodies that flood our screens.

Believe me, it’s not as easy as you might think; to take action, I mean.

You can’t force food down someone’s throat any more than you can make them chew and swallow and keep it down. You just can’t.

So I have watched as my beautiful, vibrant Maisie teeters on a tightrope. Knowing that any quick movement or panicky shout could send her over the edge.

She’s moved just far enough away from the end of the tightrope that I can no longer reach her to pull her back to safety. This bit happened stealthily, the damage done before I even fully realised.

My daughter used to adore dancing and lip-synching in her bedroom to Ariana Grande.

She loved reading and drawing and watching make-up vlogs for teens on YouTube at the kitchen table while I prepared dinner.

Now she sits surly and miserable, staring blankly at the television each night because I insist she stays downstairs at least for a couple of hours. But as soon as she is able, she darts upstairs, keen to be alone again in her bedroom.

I resist the urge to wake her now, to pull her closer to me. To kiss the top of her small, warm head, to breathe in her scent, her life essence. To beg her to just eat.

My influence on her has somehow waned to the extent that I can no longer get close enough to help her.

If someone hurts your child by beating them, hitting them, forcing them to act in a way that is obviously harmful, most parents will react in the same way.

But when someone causes such devastating harm emotionally to your child and you can’t actually prove it, what does that do to a parent? It destroys you too.

I now believe that Joanne and Piper Dent are hurting my daughter in the cruellest way possible. Destroying her self-esteem, her confidence, her enjoyment of life. They’ve done it while Maisie’s father and I were right there by her side.

Have they broken the law? Probably not.

But it’s been enough to ruin a life, and whatever it takes, it has to stop.

I feel completely justified in what I’m about to do.