The exact circumstances which led to the death of a young farmer remained a mystery after an inquest on Friday.

Bryn Anwyl Jones died after apparently being run over by the wheels of a tractor he had been driving, but what caused him to leave the cab while the engine was still running was unknown.

The 22-year-old had been spraying crops on a nearby field on June 2 last years and returned to Ty Mawr, Orion, near Denbigh, where he lived with his parents.

His father Ioan told the inquest in Ruthin that he was puzzled when he heard the sound of the tractor engine running at a constant speed, and when he investigated he found his son lying alongside the tractor in the silage yard, which was empty apart from some farm machinery.

Bryn was unconscious, and although a neighbour and police officers tried to resuscitate him paramedics certified he had died.

Home Office pathologist Dr Brian Rodgers gave the cause of death as severe head trauma and crush injuries.

Forensic collision investigator Simon Richard told the hearing that marks on the concrete wall indicated that the loader on the front of the Massey Ferguson tractor had come into contact with the wall and that the wheels can kept turning in low gear, causing the tractor to judder sideways.

Health and Safety Inspector Gary Martin said that Bryn Jones was an experienced young farmer who had undergone all the relevant training at Llysfasi College and had also taken the Safe Stop course highlighting the correct way to leave a vehicle.

"It is quite clear that Safe Stop could not have been followed," he said.

Mr Martin said Bryn had probably left the cab on the nearside while about to disconnect the sprayer from the rear of the tractor and although there were several safety features in the cab it was possible he had accidentally moved the gear lever while getting out.

Collision investigator Gary Roberts said that blood stains indicated that both the front and rear nearside wheels had probably gone over him.

Recording a conclusion of accidental death, John Gittins, coroner for North Wales East and Central, said it was difficult to fully understand what had happened, but added: "If he had followed the correct procedure and stopped the engine the incident would not have occurred."

"We know that the tractor he came into collision with was moving and caused the injuries which led to his death."

Mr Martin said that although there was nothing to indicate any problem with the tractor he would draw the matter to the attention of the manufacturers for their consideration.

Bryn, a former pupil of Ysgol Bro Cinmeirch, Llanrhaeadr, and Ysgol Brynhyfryd, Ruthin, carried out contracting work on local farms as well as working at home. He had a particular interest in poultry.

After his death £6,500 was raised in his memory for the Wales Air Ambulance and the Royal Agricultural Benevolent Institution.