"But fundamentally what is lacking is the eternal problem, which is that there is no underlying loyalty to the idea of Europe.
"There is no single authority that anybody respects or understands. That is causing this massive democratic void."
Board of Deputies president Jonathan Arkush has said: “I don’t think references to Hitler in the debate on Britain’s position in the EU helps the arguments at all.”
Labour MP Yvette Cooper, who supports the Remain campaign, accused the ex-London Mayor of using Hitler to play "nasty, nasty games".
Ms Cooper said Mr Johnson showed a "shameful lack of judgement" and was playing "the most divisive, cynical politics".
She said: "He should not try to play political games with the darkest and most serious chapter of Europe's history.
“The EU has played a critical role keeping peace in Europe ever since."
