A coroner said yesterday he was shocked to learn that a boy had drowned in a public swimming pool manned by four lifeguards. On July 16 last year, another swimmer alerted lifeguards after finding nine-year-old Chan Yuk-ping floating face down in the Tai Po pool. Recording a verdict of accidental death yesterday, Coroner Ian Thomas urged lifeguards to pay special attention to children, whether or not they could swim, especially those unaccompanied by adults. He said he was surprised the lifeguards did not notice the boy drowning. 'While I appreciate it is difficult for lifeguards to keep an eye on every swimmer and to distinguish between those playing and those in difficulty, I am struck by the fact that none of them appeared to see the boy until it was too late,' Mr Thomas said. Lifeguard Chan Yeuk-sat had told the inquest he patrolled the accident spot six minutes before the drowning but did not see the boy. Another lifeguard, Yeung Kam-yin, said his way to test whether a swimmer was in difficulty was by holding his own breath. 'If the swimmer's head had not surfaced by the time I'm nearly out of breath, I know the swimmer is not playing.' Yuk-ping had been spending a few days with his godmother, Lo Mang-lai, 46, who took him and her young nephew to Tai Po to visit her friend Leung Siu-ping, 47. Ms Lo then decided to go for a walk, leaving Ms Leung, who could not swim, in charge. Yuk-ping wandered from the ankle-deep paddling pool to the main pool, where he drowned.