A group of teenagers hid canisters of lighter gas from paramedics while their friend lay dying in an Abingdon park, an inquest heard.

Kevin Field, 16, collapsed and died as a result of inhaling butane gas at Albert Park on June 3.

Oxford Coroner's Court heard that his three friends concealed evidence from police and paramedics until CCTV footage was found showing the teenagers buying cans of butane gas from Goff's newsagent in Bridge Street.

Kevin, of Saxton Road, had been due to start work the day after he collapsed and died.

One of the teenagers told the inquest the four friends had sniffed gas together before.

The friend said that on the day Kevin died the group had sat in a circle in the park, smoking cannabis and inhaling equal amounts from two canisters round. Kevin had been inhaling immediately before he collapsed.

The teenager said: "I was making a joint and Kevin was sat opposite me. I looked up and Kevin was having a seizure. He was spinning and rolling around on the grass."

An ambulance was called and Kevin was put in the recovery position.

When paramedics arrived they found no evidence of gas canisters.

Paramedic Adam Shield, of Witney Ambulance Station, said none of the teenagers mentioned the gas.

He added: "I asked if he had taken anything and one youth said he had taken cannabis."

Dc David Evans, of Abingdon police, said police had pieced together the events from CCTV footage showing the boys buying gas from the newsagent.

Oxford coroner Nicholas Gardiner, recorded a verdict of accidental death.

He told the teenagers: "I hope the three of you have learned your lesson."