I stepped to the edge of the platform. It was the easy way out. I wouldn’t have to face what I’d done

had ‘to behave like this’ and learn strategies for ‘coping and changing’. To the best of my knowledge, no one asked the boy who coerced Roxy why he felt he had to behave like that, or made him learn strategies to respect girls of any age, but particularly girls of 13.

To this day, I have no idea if they were punished or if their parents were ever informed.

A month later, now chronically sleep-deprived, paranoid and miserable, Roxy ran away, telling me she wanted to disappear.

We called the police and the officer who helped us look for her told us the school should have reported it. ‘We are dealing with rising weekly cases of this nature,’ said the officer. ‘A girl or boy falls into the trap of sending an image of themselves naked. This is a child pornographic image and it’s illegal. Immediately, that image is used as leverage to gain more images.

‘Threats of exposure are always part of it, which makes it coercive. The threats continue until the images are distributed, discovered, and life as they knew it is over.’

I needed Roxy to come home so I could tell her that life wasn’t over, but she was no longer listening to my voice.

ROXY:

MuM took away my phone. She wanted to treat me like a stupid teenager.

For her, this was the beginning of the drama, but it had already been months of hell for me.

That weekend, I went shopping in London with a family friend who was my age and she insisted we go into Victoria’s Secret.

As soon as I entered the shop, I couldn’t breathe. The huge photos of models wearing practically nothing loomed over me. I ran outside and slid down the wall until I was a ball on the floor.

Alone on the Tube platform later, when I heard the train coming, I stepped forward to the very edge. It was the easy way out. I wouldn’t have to face what I’d done . . .

I told myself I was a messy, attention-seeking, dumb, teenage girl. I was the trainwreck that went from model student to stupid slut. But, in the end, I didn’t think I had the guts to actually end it.

Back at school, I took all the insults — the fired spitballs, the rolled-up notes saying ‘SLAG’ — and the only way I found any relief was to go somewhere alone and take out the blade I’d unscrewed from a pencil sharpener.

I made bright-red cuts across my arms and up my torso. I wanted to feel the sting. I wanted to watch as the blood kept oozing.

In lessons, I used the blade to shave away at my fingernails under the desk until, eventually, I got to the skin underneath. The pain was excruciating.

GAY:

OVeR the next two months, Roxy struggled through lessons until the school sent her home, aware she was cutting and unable ‘to guarantee her safety’ any more.

I diluted Dettol in a bowl and rolled up her sleeves to clean her injuries. The cuts appeared superficial but, my God, there were so many of them, crisscrossing her snow-white skin like striations in marble. I was crippled with fear and guilt.

The photos damaged her, but the blame broke her.

Her mental health began a dangerous downward spiral, taking her to a dark and terrifying place. She started to hear mean, accusing voices laughing at her, calling her names, and we, the people who loved her, couldn’t reach her.

While driving at 60mph to a desperately hard-won appointment at Child and Adolescent Mental Health Services, she suddenly opened the door and tried to get out. The ‘people’ told her it wasn’t safe in the car.

I couldn’t leave her alone, not even to wash. I felt the extraordinary complexity of being needed and hated in equal measure.

And yet Roxy did crawl out of the well. Music helped, nature helped, powerful anti-psychotic drugs probably saved her life.

She left that school and, after nine months at home, she went to a crammer and took her GCSes.

A little over four years after she sent that first photo, she celebrated her 18th birthday with a party. Her dad and I hugged each other and burst into tears of pride. We felt joy because she had a few precious friends who had stood by her; and relief, because she was alive.

When her A-Levels were cancelled during the lockdown, Roxy and I decided to write a book together. But we could barely be in the same room, so different were our accounts of what happened.

So she disappeared into one room to write, I into another. Only when we had finished did we each read the other’s version and start to understand.

I hope you know now, Roxy, that you were a child who deserved to be protected by us, by the school who should have made it clear from the very first moment that this was not your fault, and by me — I should have known what was happening to you and I should have stopped it. I will carry that sadness and regret to the grave.

Today, Roxy is studying maths and neuroscience at university, and I am amazed at how powerful her brain is. She has been broken — we all have — but with every day that passes, she becomes stronger and more beautiful.

AdApted from When You Lose It by Roxy and Gay Longworth (£16.99, Welbeck), out on July 7. © Roxy Longworth and Gay Longworth 2022. to order a copy for £15.29 (offer valid until July 7, 2022; UK p&p free on orders over £20), visit mailshop.co.uk/books or call 020 3176 2937. Some names have been changed. For confidential support, call the Samaritans on 116 123.