French President Francois Hollande has made it clear that he wants Britain to continue to be part of the European Union (EU) and has now warned the country that there will be "consequences" if they decide to exit, which will directly affect immigration and economy.

Speaking to reporters following the Anglo-French summit in Amiens in northern France, Hollande said: "There will be consequences if the UK is to leave the EU, there will be consequences in many areas, in the single market, in the financial trade, in development, in the economic development between our two countries.

"It doesn't mean that everything will be destroyed, I don't want to give you catastrophic scenarios but there will be consequences."

Earlier, French Finance Minister Emmanuel Macron had hinted that the UK border controls in Calais could come to an end depending on the British government's final call on the EU referendum and the camp could be moved to Kent. When confronted about the same, Hollande said: "I don't want to scare you, I just want to say the truth — there will be consequences."

London Mayor Boris Johnson, who is pro-exit, responded to the veiled threat saying: "I would say: Donnez-moi un break. There's absolutely no reason why that treaty should be changed."

"It was an intergovernmental treaty; it was the Le Touquet treaty. It was signed between the British government and the French government. It's not in the French interests to want to do that and it's just the usual flapping and scaremongering," he said in south London.

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Playing a diplomatic card, UK Prime Minister David Cameron pointed out that it was important to take heed to advice offered by countries that are also looking out for what is best for the UK. "I would say to people, when you have got the leaders of countries that wish Britain well like New Zealand, Australia, Canada, America, France — when you get messages from them, that's worth listening to.

"When business organisations both representing large and small businesses are saying there are risks to Britain leaving the EU, I would say, listen to those people," he said at the joint press conference in Amiens.

While speaking at a conference of the British Chambers of Commerce in London, Germany's finance minister Wolfgang Schaeuble said Europe would be "less stable and more volatile" without Britain in the EU.

When asked what Germany's reaction to Britain leaving the EU would be, Schaeuble said: "We would cry. But I hope we will not."