An oil company boss turned into a human fireball and died after using petrol to light a bonfire, a coroner has been told.
Alan Gaynor, of Denner Hill, Buckinghamshire, had drenched the pile of wood with the flammable liquid from a full jerry can.
Although he moved the can safely away, he did not realise he was still surrounded by evaporated gas when he struck the match.
Within a split second, flames ripped through his clothes and burned his body as he rolled around in desperation.
The tragedy was called a "bizarre and cruel" accident by a coroner in High Wycombe, Buckinghamshire, on Tuesday.
48-year-old Mr Gaynor, the chief executive of London-based British-Borneo Oil and Gas, was working on his farm with his brother-in-law.
Buckinghamshire coroner Richard Hulett heard how Mr Gaynor had taken a year off from the oil company to run the smallholding in Great Missenden, Buckinghamshire.
Mr Gaynor's brother-in-law Walter Creagh was visiting him on 28 May this year when the tragedy happened.
He said: " He made his way to the shed and took out a jerry can and took it to the lower field.
Mr Creagh found his brother-in-law rolling in the grass trying to extinguish the flames.
He said: "Smoke was coming from him but he was conscious, alert and knew what was happening."
He was rushed to Stoke Mandeville Hospital's specialist burns unit in Aylesbury and transferred to Mount Vernon Hospital, Uxbridge, Middlesex, where he died two weeks later.
Consultant pathologist Dr Yoon Chai told the inquest Mr Gaynor had died of an "inflammation of the heart", a complication from the severe burns.
Mr Hulett said that the executive, who leaves a wife and son, had taken the proper precautions when lighting the fire on the Bank Holiday Monday.
Mr Gaynor had moved the jerry can 15ft away from the fire before going back to light a match.
Mr Hulett said: "This was an accident clearly caused as he was pouring petrol to ignite a large bonfire.
"Bizzarely and cruelly, people do walk away to remove a petrol can from the area, which is the safe and sensible thing to do.
"However, petrol vapour around the bonfire can create a fireball in a split second causing these tragic accidents."
He recorded a verdict of accidental death on Alan Gaynor, of Denner Hill.