One of the young "Wild Boars" footballers rescued from flooded Luang Cave in Chiang Rai in 2018 has died suddenly in England.

The death of teenager Duangphet “Dom’’ Phromthep came as a shock to his family and friends.

The cause of death was unclear. Unconfirmed reports in British media said he sustained a head injury. He had signed up for the Brooke House College Football Academy in Leicester, England, last year.

Social media was inundated with messages of grief and condolence when the news broke on Wednesday.

The Zico Foundation posted a message and a photo of Duangphet, or Nong Dom, who had received a football scholarship from the foundation.

Initial reports said that there was an accident, a fall, and Duangphet was injured. He was admitted to hospital and put on a ventilator but later died.

Relatives in tambon Wiang Phang Kham told reporters they were informed the boy had been injured in an accident that led to his death. Details would be given out by the boy’s football club in England, they said.

Duangphet was the captain of the Wild Boars football team whose rescue from a flooded cave captured the attention of the world in 2018.

Between June and July 2018, Thai and international rescue teams scoured flooded Luang cave in Chiang Rai's Mae Sai district to find 12 "Wild Boar" footballers aged between 11 and 16 and their 25-year-old assistant coach, who went to explore the underground complex on June 23 after football practice.

They were trapped inside by a sudden storm and flood for 17 days before being finally found by two British divers. A complex and dangerous rescue followed. One rescuer died in the flooded cave.