I've heard sad stories of people who get their visa successfully, they come to the U.K. everything is fine. Then they have a holiday in America or someplace and find they get refused entry when they come back to the U.K. Does anyone know precisley why this happens? I've heard this has happened to a Thai girl, and also an American/Spanish girl, but they are vague about the reasons why it happened...I'm sure none of us want to get into that situation...can anyone shed any light as to why this apparently sometimes happens?