A missing scuba diver nearly sparked a full scale search and rescue operation in South Africa -- until the man's mother informed rescuers that her son had in fact been locked by the police. The National Sea Rescue Institute mobilised on Wednesday night after an emergency call that a man had not returned from a late afternoon dive at Cape Town's St James beach. But all activated rescue services -- including a police helicopter with a thermal imaging detector -- were called off after a phone call to the missing 42-year-old's family, said NSRI spokesman Craig Lambinon. "Fortunately the mother of the missing man informed us that her son had just called her and that he was locked up in the cells of a police station... for allegedly being found diving in a protected marine reserve without a permit." The alarm was raised by the man's friend who grew anxious after darkness fell. "All rescue resources were stood down as they were no longer required and the man's friend was relieved to find out that he was alive and well," said Lambinon. "It appears that while the friend had gone for a walk along the beach law enforcement agencies had come across the scuba diver diving and they had arrested him for apparently not having a dive permit."