Ed Balls has accused Boris Johnson of displaying an "Ill-judged and irresponsible lack of judgement" for dragging Hitler in to the EU referendum debate.
The former Labour shadow chancellor said Johnson was trying to "distract attention" from other "big issues" in the campaign.
Speaking at a pro-EU campaign event alongside George Osborne and former Lib Dem cabinet minister Vince Cable, Balls said Johnson was "attention seeking".
Today, the former London mayor, who is campaigning for Brexit, defended using an interview in the Sunday Telegraph to compare the EU to Hitler’s attempt to occupy the continent.
Johnson said today: "Over the last few thousand years there have all sorts of attempts in Europe to recreate the dream of the Roman Empire. Very often that has been done by force. The EU is different. It’s trying to do it in a more bureaucratic way.
"There is very good argument against the lack of democracy in the EU. Over the last 2,00 years people have made repeated attempts to unify Europe by force. The EU is a very different project but it is profoundly anti-democratic."