Former London mayor and leading Brexit campaigner Boris Johnson sparked fury Sunday after he compared the European Union with Adolf Hitler's Nazi Germany.

His remarks, viewed by Remain campaigners as inflammatory, fueled a war of words in both camps, with some Leave members of Prime Minister David Cameron's Downing Street cabinet leaping to Johnson's defense.

Johnson made his remarks in the Sunday Telegraph in which he warned "that while bureaucrats in Brussels are using different methods from the Nazi dictator, they share the aim of unifying Europe under one authority".