Steve Humphries, father of 14 year-old Joe Humphries, who died last October from SADS (Sudden Adult Death Syndrome), is part of a team cycling 624 miles around Rutland Water to raise awareness of the condition. Joe was from Rothley in Leicestershire.
624 is the average number of young people who die from SADS each year.
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The 14-year old student had moved from Nottingham to London recently.
Ayoub Majdouline, 18, was arrested in Wembley, north west London, on Saturday morning, Scotland Yard said.
Jaden was stabbed to death on January 8 after he was rammed off a moped by five men in a black Mercedes.