Britney Spears has been banned from a political party conference-for being too sexy.The blonde singer, who is a supporter of George W. Bush, was due to play at the Republican National Convention in New York.But Britney, whose raunchy image was seen as 'potentially doing more bad than good' for the party, was rejected by top politicians after it was leaked that she was to make a surprise appearance.An insider said, 'We are a serious political party and don't need Britney to promote us.''Besides, with the headlines she has been recently attracting it would do more harm than good to the...