The British cave diver who played a leading role in the rescue of 12 Thai boys and their coach last year has spoken of how sedating the children was necessary to complete the mission safely.

John Volanthen, a British cave diver who specialises in rescues, and his colleague Richard Stanton, were the first to find the group who were stranded in the Tham Luang cave in Thailand—a discovery which led to their eventual rescue.

Speaking to a medical audience at the Risky Business conference in London this week, Volanthen told how the rescue wasn’t a “miracle” but the result of meticulous planning, rehearsing each step, and taking calculated risks. All lessons that were translatable to healthcare, he said.

“When the incident commander announced to the world that the boys were …