Two British divers who helped rescue a Thai youth football team and their coach from a flooded cave in northern Thailand had earlier saved four adults also trapped in the underground labyrinth, according to a new report about the daring operation that gripped the world for two weeks.

The 12 boys from the “Wild Boars” club and Ekapol Chanthawong, their coach, were cut off by rising floodwaters when they tried to explore the Tham Luang cave on June 23, and discovered nine days later by Rick Stanton and John Volanthen, who captured the moment in an astonishing video.

However, in a previously unknown twist, the two caving experts thought they had found the boys three days earlier when they surfaced from the zig-zagging submerged passageways into one of the cave’s chambers to find four people.

In fact, they had come across a group of inexperienced Thai water company workers who had got into difficulty during the chaotic early days of the rescue mission.

For 24 hours, nobody had noticed they were missing and the men were in a life-threatening situation as murky waters rose quickly.