Popular teenager Luke Francis died from a heart condition he never knew he had, his grieving mother revealed today. 

The 19-year-old's mother Rosie, who has launched an appeal for a heart charity in her son's memory, said police at first believed her son was the victim of a hit-and-run. 

But detectives have told her they are now satisfied that Luke, who was found next to his BMX bike in Shearer Road, Buckland, Portsmouth on November 23, died of natural causes. 

An inquest will determine the exact cause of Luke's death but Mrs Francis has been told a heart attack caused by a condition that Luke, of Palmerstone Road, Southsea, was unaware of is the most likely cause. 

Mrs Francis, of Laburnum Grove, North End, called on Luke's many friends to donate to the charity Cardiac Risk in the Young which has helped her understand he son's death. 

And she wrote an emotional account describing the night of Luke's death and the following weeks, which The News publishes in full today. 

A post-mortem examination has indicated that Luke died of an unknown heart problems and samples have been sent to London for further analysis by a top cardio-pathologist. 

Mrs Francis came across CRY as she did her own research into what could have killed her son. 

"It has helped me," she said.  "People can put their own stories on the website, and I've read a lot of them. 

"It's so many young people.  They should be burying you, not the other way round. 

"But this happens to 12 people a week - there are 11 other families like us that have gone through the same thing that week. 

"Please send your donations in memory of Luke to CRY. 

"He liked to smoke and drink, and when I would tell him off about it, like a mum does, he would always tell me: "I'm not going to get past 23 so just chill out."  It's weird."

Rosie Francis is asking that people make donations to Cardiac Risk in the Young in Luke's memory.  Go to c-r-y.uk/index.htm