A runner has died while competing in an extreme night time race in the Scottish Borders.

The 48-year-old woman was participating in the Mighty Deerstalker event in Tweeddale on Saturday when she collapsed.

She is understood to have fallen shortly after crossing crossing a shallow creek a mile into the ten-mile course at about 6pm.

A medical team was reportedly at the scene within minutes, assisted by an off-duty paramedic.

The woman died in an ambulance on the way to Borders General Hospital, however.

A spokesman for Organisers Rat Race Adventure Sports: "Rat Race Adventure Sports will give full assistance to the appropriate authorities.

"Our heartfelt thoughts and condolences are with the family and friends of the deceased."

A Police Scotland spokesman added: "The 48-year-old was treated by the Scottish Ambulance Service and was taken to Borders General Hospital. However, she passed away while en route.

"Enquiries are continuing, however there appear to be no suspicious circumstances surrounding this death and a report will be sent to the procurator fiscal."

The Mighty Deerstalker is considered one of Britain's most difficult night races and includes stretches over mountains and through rivers and forests.

Participants are asked to confirm they are fit to compete before taking part in the race.