A mother from Watton appeared on ITV's This Morning to talk about how she secretly gave her son cannabis to save his life.

Eastern Daily Press: Deryn Blackwell at Wayland Academy in Watton with his mum Callie, in 2015. Picture: Ian BurtDeryn Blackwell at Wayland Academy in Watton with his mum Callie, in 2015. Picture: Ian Burt

Callie Blackwell's son, Deryn, suffered from leukaemia in 2010 at 10 years-old and was later diagnosed with Langerhans cell sarcoma in 2012, a rare cancer which only affects one in 7bn people.

Speaking on the show, Mrs Blackwell said her son underwent three failed bone marrow transplants and was told by doctors that a fourth attempt would be his last chance.

But not long after the operation, Deryn trapped his finger which subsequently got infected. With no immune system to fight it off, Deryn was given three days to live.

'He was being kept alive by antibiotics and was in a lot of pain.' Mrs Blackwell said.

Eastern Daily Press: Deryn Blackwell in hospital. Picture: Supplied.Deryn Blackwell in hospital. Picture: Supplied. (Image: Archant)

Deryn told TV presenters Holly Willoughby and Phillip Schofield that he had planned a fancy dress themed funeral and chosen costumes for guests, adding: 'Once you accept it [death], it becomes very calming, it's nice in a sense.

'After four years it was enough.'

Mrs Blackwell started to look for other options online to help her son and came across Bedrocan - a cannabis based painkiller not available in the UK. She said: 'Through lots of research I turned to the internet and cannabis kept coming up.

'I asked the doctor for Bedocran, I wanted to go through the proper measures, but it is not licensed for children.'

Eastern Daily Press: Deryn Blackwell, then aged 14, with his dad, Simon. Picture: Denise BradleyDeryn Blackwell, then aged 14, with his dad, Simon. Picture: Denise Bradley (Image: Archant)

Mrs Blackwell decided to go ahead and administer the drug illegally, adding: 'What have I got to lose? He's dying anyway.

'The effect of it blew my mind, we noticed after thirty minutes to an hour he was chilled out.'

After 75 days, Deryn's blood count started to rise and his finger began to heal. Mrs Blackwell said she even withdrew the cannabis to test the effects and noticed his blood count declined.

Phillip Schofield warned viewers that cannabis is an illegal drug in the UK and what Mrs Blackwell did is a an offence. He also said cannabis is not a cure and is just something that worked for Deryn Blackwell.

Mrs Blackwell retells the story of her son's miraculous recovery in her new book The Boy in Seven Billion, written with journalist Karen Hockney.

Deryn, now 17, told Holly and Phillip that he dreams of becoming a chef.