Britain sent the largest contingent to the jamboree, the first global scout gathering since the pandemic.

Matt Hyde, UK Scouts' chief executive, told Reuters the group decided to withdraw its more than 4,000 scouts on Friday for their own safety. The U.S. scouts followed.

"We were concerned that the toilets weren't being cleaned frequently enough. It wasn't safe in there. And there was rubbish building up as well," Hyde said.

"There were concerns around food and particularly those with dietary requirements that weren't getting the food that they needed so they were eating less," he added.

"We didn't think it was safe for the young people and the adult volunteers."

Organisers said on Monday tens of thousands will be evacuated from the campsite, in an area of reclaimed land in southwestern Jeolla province, to get them out of the path of a looming typhoon.

The storm comes after one of the worst heatwaves to hit South Korea in years, which caused hundreds of scouts to fall ill. Hyde said UK Scouts also had concerns about the medical services at the campsite.

Parents and the public have criticised the organisers for not anticipating the heat and the challenge of hosting so many people.

Each UK scout spent around 3,500 pounds ($4,450) on the trip with many relying on fundraising or donations, Hyde said, adding that he would encourage an independent inquiry be held into the jamboree.

HUGE MOSQUITOES

Olaf Clayton’s daughter, Gabriela, 16, travelled from the family’s home in Madrid, Spain, with British Scouting Overseas to join the jamboree.

He said his daughter had spent 18 months conducting bake sales, teaching English and working in catering while the 1st British Scouts Madrid ran fundraising events for her to save the money to attend. She also learned Korean phrases and studied its culture.

He said she had been "absolutely devastated" to hear they were being pulled out, but that the sanitary and climactic situation worsened quickly.

"By the time they were leaving it was hell – kids were fainting waiting for the buses to arrive," he said. "There was no shade, all activities were cancelled and there were huge mosquitoes.

"Gabriela is quite a tough cookie but she said there were 'funny things' coming out of the ground. There was a snake under her bed – thankfully the Bangladeshi scouts knew just how to deal with snakes."

He said he and his wife had had no qualms about their daughter travelling to South Korea, a "massive scouting nation and a first world country known for its organisation".

"Gabriela will have war stories and learned a lot from it, so there are positives but not so much for South Korea and its reputation for hosting this kind of thing," he said.

Provincial governor Kim Kwan-young apologised on Sunday for not being well prepared, and officials sent in more medics, water trucks and air conditioners to the campsite to help with the heat-related illnesses.

The South Korean organising committee did not immediately respond to a Reuters request for comment.

Poland is due to host the next World Scout Jamboree in 2027.

"It is critical that the lessons are learned," Hyde said. "Things were promised, they weren't delivered.