Joanne Mison was devastated when her husband found her teenage son, Tyler, hanging by his tie from his cabin bed. The 13-year-old was a happy, popular boy with no apparent problems – she was certain he hadn't meant to take his own life.

Shocked and devastated she turned to the internet to try to find an explanation and came across the terrifying ‘choking game' trend – where teenagers try to get a high by cutting off their oxygen supply.

As she read about the signs that children had been indulging she was sickened – bloodshot eyes, neck marks and headaches were all signs that kids had been playing the game. Tyler had them all.

“I was absolutely distraught when we lost Tyler,” she says, “I couldn't understand why my son would kill himself.”

“My initial reaction was to think it was suicide – it's certainly what it looked like. But that thought quickly left my head – I knew Ty and I knew he would never intentionally take his own life. I had to find out what had happened.

“Then, after a Google search, I found out about the choking game and it all fell into place. I couldn't believe Ty had been so silly – why would he experiment with something so dangerous – and keep doing it? Then the guilt kicked in – if I'd known about it I could have spotted the signs and stopped him before it was too late. I was desperate to let other people know and prevent another death.

It is believed the choking game, also known as Pass Out, Blackout and Space Monkey, has already claimed the lives of more than 100 children in America. There are no official statistics for England, but campaigners put the number of deaths at at least 86, and many believe a number of young deaths from the choking game have been mistaken as suicides.