A search is under way for the TV doctor and newspaper columnist Michael Mosley, who went missing after going on a coastal walk on the Greek island of Symi. The 67-year-old, known for his appearances on The One Show and This Morning, was last seen when he set off hiking along St Nicholas beach at 1.30pm local time (1130 BST) on Wednesday. His wife, Dr Clare Bailey, alerted authorities after he failed to return by 7.30pm, but they were unable to locate him overnight. A post has been shared in a local Facebook group appealing to anyone on the island of about 2,500 people who may have seen Mosley. It said: “A search and rescue team is coming from Athens with drones and other more sophisticated equipment to extend the search. “Have you seen this man? He set off to walk back from St Nick’s at about 13.30 and failed to make it home. His friends are concerned as it is 6 hours since they last saw him. His name is Dr Mike Mosley and he is a familiar face for many British people.” Greek police told the Guardian a helicopter and specially trained dogs were due to join what has become a massive search for Mosley on the remote Aegean isle. “We’ve got every service possible out there looking for him,” said a police chief overseeing the operation who spoke on condition of anonymity. “He was officially reported missing this morning and now there are police, firemen and volunteers involved in the search.” A drone was also being used and the Hellenic coastguard has been instructed to patrol the island’s rugged coast. “We are working on the assumption that he might have been affected by the heat, that he might have slipped and fallen perhaps from a height. Right now nothing is being ruled out.” A senior security official involved in the mission said the search for the Briton had begun to resemble “a thriller”. Mosley, he said, was being hosted by friends on the island “where distances are short”. And, yet, there had been no sightings of him. “It’s crazy, it makes no sense,” he said. “How can somebody just disappear in broad daylight, in the middle of the day? If something had happened to him we would have found him on, or near, the path he was walking along on his way back to the port where he was staying with friends. And, yet, all these hours later there’s nothing.” Rumours of a sighting near a bus stop in the resort of Pedi were dismissed after a CCTV camera was checked, another police officer said. The search is expected to be further expanded on Friday when extra squads of police arrive from Rhodes along with dogs trained by the fire brigade. Mosley is a columnist for the Daily Mail and has made a number of documentaries about diet and exercise, including the Channel 4 show Michael Mosley: Who Made Britain Fat? He was also part of the BBC series Trust Me, I’m a Doctor. He lived with tapeworms in his guts for six weeks for the documentary Infested! Living With Parasites on BBC Four. Mosley is also credited for the rising popularity of the 5:2 diet, which involves fasting for two days a week to lose weight. He has previously been named “medical journalist of the year” by the British Medical Association.