AT 47, Brett Hackett was fit enough to run marathons - his post mortem proved it.

An inquest was told of no reason why Mr Hackett should have died so suddenly earlier this year when he "looked after himself" and even had his asthma well under control.

Pathologists put Mr Hackett's death down to a rare condition that medical science is not yet advanced enough to fully understand.

Herefordshire Coroner David Halpern agreed, saying evidence suggested Mr Hackett was a victim of Sudden Adult Death Syndrome (SADS), a natural cause about which little is known.

Paramedic Ian Hughes told the inquest Mr Hackett had no obvious injuries and "looked like he was asleep" after falling off his bicycle near his Evesbatch home in February.

Mr Hackett was taken to Hereford County Hospital but never recovered and casualty consultant Andrew Ballham said, in a statement, that he was probably dead as the ambulance arrived - if not soon after.

Mr Hackett had been following his daughter, Natalie, who was on horseback and heading up a steep slope when she saw her father "wobble and fall".

She told the inquest how she went to help and heard him "groaning".

Pathologist Dr Frank McGinty said a post mortem examination of Mr Hackett showed brain swelling and vomit inhalation consistent with "the mechanism of dying" but no obvious cause for death to occur.

The inquest heard how Mr Hackett controlled his asthma with an inhaler, looked after himself well and was "fit enough to run marathons".

Analysis of Mr Hackett's heart found no abnormalities at all, leaving SADS as the only explanation given the evidence available, said Dr McGinty.

Recording a verdict, Mr Halpern said that the death was due to natural causes that medical science was "not yet advanced enough to ascertain".