Severe flooding and mudslides in southern Thailand have killed 21 people, stranded thousands of tourists and threatened to delay shipments of rubber in the world's largest rubber-producing country, authorities said today. Trains to the region have been cancelled and three airports have been shut, including one on the popular island of Koh Samui. As well as Koh Samui, foreign tourists - including Britons - have also been stuck at resorts in Krabi and Koh Phangan. The Thai navy evacuated about 1,200 people from Koh Samui and Koh Tao, a remote island popular with backpackers. Stranded tourists sit on the floor of Samui airport in the flooded resort island of Koh Samui, Thailand, waiting to escape the island. Three airports in the south of the country have been closed so farThailand's...