Fears that the Brexit will result in massive economic consequences
Some of Europe's top politicians have spent the day calling for the UK to remain in the EU.
French politicians have been setting out scenarios for Britain outside the EU.
One government minister's warned a vote to leave in June's referendum could result in a migrants camp moving from Calais to southern England.
The French president Francois Hollande warned of 'consequences' if there's an 'out' vote in June's referendum.
And speaking at a news conference with David Cameron, president Francois Hollande said it'll hit trade between France and the UK.
He's been accused of 'scaremongering' by leave campaigners.
Meanwhile Germany's finance minister's been asked what his country would do in the event of a Brexit: