The father of a teenager who collapsed at a music event at the O2 and later died has warned that those who take drugs "can pay the ultimate price".
"Wonderful, vibrant" Emily Lyon, 17, was among six youngsters who went to the Red Bull Culture Clash on June 17 and were taken to hospital after apparently taking illegal drugs.
Today her father Steve Lyon, from Teddington, south-west London, said: "We are absolutely devastated at what has happened and we're struggling to come to terms with it.
"Emily was a wonderful, vibrant young lady. She was a loving daughter and a caring sister, who was much adored by her vast circle of friends.
"It can be seen how these so called 'recreational substances' can result in such tragic consequences for so many people. Those who take them can pay the ultimate price."
A 16-year-old boy who was also at the event was taken to hospital having apparently taken drugs, and four others were taken to hospital as a precaution but then discharged.
Emily's death is currently being treated by police as unexplained. A post mortem examination proved inconclusive and officers are awaiting the results of toxicology tests.
Scotland Yard said a 17-year-old boy was arrested in Kingston on Saturday on suspicion of possession of MDMA, also known as ecstasy, with intent to supply, and bailed until late August.