In a dramatic interview with the Telegraph, he warns that while bureaucrats in Brussels are using "different methods" from the Nazi dictator, they share the aim of unifying Europe under one "authority".

But the EU's "disastrous" failures have fuelled tensions between member states and allowed Germany to grow in power, "take over" the Italian economy and "destroy" Greece, he warns.

Napoleon, Hitler, various people tried this out, and it ends tragically. The EU is an attempt to do this by different methods.Boris Johnson

Mr Johnson invokes Winston Churchill's war-time defiance, urging the British people to be "the heroes of Europe" again, set the country free and save the EU from itself by voting to leave in the referendum next month.