Capitalizing on the restive mood, Mr. Farage, the U.K. Independence Party leader, took out an advertisement in The Daily Telegraph this week inviting unhappy Tories to defect. In it Mr. Farage sniped that the Cameron government — made up disproportionately of career politicians who graduated from Eton and Oxbridge — was “run by a bunch of college kids, none of whom have ever had a proper job in their lives.”