I slipped into a coma after drinking dirty water out of River Thames

Singer, 37, nearly died after charity filter demo went wrong

and viruses – next to a Thames sewage outlet.

Speaking for the first time about the incident yesterday, Darius said: “I drank the water for the video and raised the funds but, when I went to Glasgow to see my mum for her birthday, I collapsed.

“It turned out I had a cerebral oedema where your brain swells bigger than your skull. Dad saved my life. He got me to hospital. They diagnosed it quickly.”

He’d caught an inflammatory virus from the Thames, which left his immunity low, then picked up bacterial meningitis.His mum Avril, who was having chemo and radiotherapy for breast cancer when her son collapsed in 2015, kept a bedside vigil after he lapsed into a coma.

Darius added: “As I came out of the coma, I remember my mum sitting beside the bed.

“It felt upside down and wrong because my mum was going through cancer treatment.

“Yet she was next to me with tears in her eyes telling my brother that they almost lost me.”

As Darius recovered, he was horrified that his charity’s water filters might have been to blame.

He said: “I suddenly got a shock, worrying that the water filters didn’t work and that they had been sent off and that other people could have died from this.

“But other people who drank the water didn’t get sick and it was a huge relief when we found out the water filter I used was a display model without a filter.

“So, in an inadvertent way, I proved the water filter worked because the others who drank from a bottle with a filter in it didn’t get sick.”

Darius is a founding ambassador of the non-profit Fresh2o with actress Keira Knightley and F1 racing driver Lewis Hamilton.

The charity’s Candice Farmer said: “When Darius got sick, he realised the Thames water was the cause and it soon became clear he had used a water bottle minus the correct anti-viral filter.

“We work in countries like Madagascar, where the drinking water contains parasites and can make people very ill.”

Avril has been given the all clear after her cancer battle, while his dad, gastroenterologist Booth Danesh, also fought back from the disease a decade ago.

The star said: “My illness knocked me off my feet and I was bed-bound for three months and picked up a new respect for what my parents went through.”