A police officer leads away a youth who threw an egg at British opposition Conservative party leader David Cameron, unseen, during his election campaign visit to Cornwall College in Saltash, near Plymouth, south-west England on Wednesday April 21, 2010. The politician laughed off the missile, which hit him on the shoulder as he left a college in the town of Saltash, saying it was the "first of the campaign." (AP Photo/Johnny Green, PA)