Nigel Farage has always been a master of political innuendo. As a schoolboy in South London in the early 1980s, when neofascists and racists rioted across Britain, Mr. Farage’s favorite prank was to scrawl “NF” on the classroom chalkboards. The joke was that these were his initials and those of the National Front, the leading neofascist group at the time. The splendor of Mr. Farage’s school, Dulwich College, added to the transgression. Designed by the son of the architect that built the Palace of Westminster, the school — all haughty buildings and pristine grounds — surely seemed a world away from far-right thuggery. Yet Mr. Farage has always been curious about the potential for combustion, comic and otherwise, when those two worlds collide.