Wellington teacher Chris Jones was knocked unconscious before death at Dunkeswell Airfield

Chris Jones, 61, jumped from 6,000ft above Dunkeswell Airfield, Devon last July.

His parachute, which he had packed himself, opened immediately instead of it taking four to five seconds as expected.

He died from multiple injuries.

Dr Elizabeth Earland, coroner for Exeter and Greater Devon, reached a narrative conclusion at the inquest last Wednesday.

She said that the “fast and hard opening” of the parachute was “due to the manner of its packing”.

She added: “This rendered Mr Jones unconscious and forced the left-side braking toggle to release, causing an uncontrollable spiral descent. Death was instantaneous.”

Dr Earland said she hoped the death would raise awareness of “the dangers of this sport and the importance of proper packing of parachutes”.

Mr Jones, from Pontyclun, Rhondda Cynon Taff in South Wales, was head of Chemistry at Wellington School.

A report by the British Parachute Association (BPA) found no fault with the equipment.

Jeffrey Montgomery, BPA safety and technical officer, said Mr Jones said a parachute opening too quickly could cause serious problems.

And he said Mr Jones experienced “an almost instantaneous opening of his parachute”, which could have caused him to fall unconscious.

He said parachutes should normally take between four and five seconds to fully open.

Mr Montgomery said such “hard” openings could be caused by untidy packing of a parachute and could “take your breath away”.

Mr Jones had also been advised to look at the way he packed his parachute but it had been marked as serviceable less than a week before his death, the inquest heard.

A post-mortem examination found Mr Jones suffered with moderately severe coronary problems.

However, the pathologist could not be sure they had caused him to lose consciousness during the descent.

The BPA has recommended that parachutists should be reminded of the importance of packing their parachutes correctly following Mr Jones’ death.