Prime Minister Theresa May and French President Francois Hollande have reached a "very clear" agreement to keep Britain's border controls in Calais, dispelling fears that UK's decision to leave the European Union will trigger moves by France to push the border controls back to British soil.

The deal was made after May went to Paris to meet Hollande in the second leg of her trip to Europe ahead of Brexit talks on Thursday (21 July). May described the talks with Hollande on the future of the UK outside the bloc as "excellent" and "open".

The deal with Hollande will come as a great first success for May, after the Remain campaign previously claimed that a Brexit will see the border controls returning to the UK and that there will be Calais-like jungle camps for illegal immigrants in Dover.

"We are both very clear that the agreement should stay," May said. Hollande added that the agreement is useful to both countries. "We consider it as our duty ... to apply it and also to improve it," he said in the joint news conference.

He added: "Le Touquet ensures that we can say to migrants that there is no point coming to Calais as they will not be able to cross it." British border checks in Calais was set up 13 years ago under the Le Touquet Treaty.

The 2003 Treaty allows British border guards to check for illegal immigrants hiding on lorries, cars and trains before they head through the Channel Tunnel and on to the ferries.

Despite May's first coup as the prime minister, there are concerns that the deal with France may unravel if Hollande fails to retain the presidency in elections scheduled for April, 2017. His rival and current frontrunner, Alain Juppe, has made his stance on the issue clear - he wants the UK to take control of its own borders and on its own soil. The centre-right Mayor of Bordeaux had reportedly said: "We must move the border back to where it belongs."

May secures deal on Calais border checks
French President Francois Hollande greets UK Prime Minister Theresa May at the Elysee Palace in Paris on 21 July 2016Reuters

Juppe is not the only person in favour of UK border controls returning to Britain. Calais Mayor Natacha Bouchart has asked for a change in the agreement, while former minister and newly-elected president of the Calais region, Xavier Bertrand, has said France should not be responsible for stopping migrants from making illegal crossings to the UK.

Hollande also took assertions further, assuring British citizens living and working in France that they could stay there for "as long as they like", stressing that he expects a reciprocal agreement to be reached for French citizens who reside in the UK.

They also agreed on greater cooperation between the UK and France on security and anti-terror measures.

However, the newly elected PM may not have secured everything that she would have liked to. Hollande still insisted on his earlier stance that London will not have access to the single market without agreeing to the free movement of people. He has taken on a similar position on the topic to that of German Chancellor Angela Merkel.

He also stressed that while he respected the UK's decision to leave the EU, the uncertainty triggered by dragging out the process would be bad for the whole of the EU and its economy.