AMERICAN president Barack Obama's half brother was REFUSED a visa to enter the UK after being accused of an attempted sex attack on a young girl in Berkshire. The News of the World can reveal that Kenya-based Samson Obama tried to get into Britain on his way to Washington for his family's big day, the historic inauguration in January. But eagle-eyed immigration officials at East Midlands Airport, using the latest biometric tests, discovered he was linked to an incident here last November. The hi-tech database revealed that Samson -who manages a mobile phone shop just outside Nairobi-was the same man...