Could Brexit help migrants get to Britain? Not so fast

Hopes that Brexit could provide a ticket to Britain for thousands of migrants languishing in squalid conditions in northern France are illusory, the French government says.

The president of France's North region, Xavier Bertrand, was among several politicians who challenged a bilateral accord that is at the root of the migrants' plight within hours of Britain's vote to leave the EU.

The so-called Le Touquet accord, reached in 2003, effectively moved Britain's border with France to the French side of the Channel, where migrants fleeing war and poverty in the Middle East, Africa and Asia are massed.

Looking ahead to a possible Brexit back in March, outspoken Economy Minister Emmanuel Macron said a Brexit would mean "the migrants will no longer be in Calais".

But Interior Minister Bernard Cazeneuve quickly reprimanded Macron for the comment, saying: "We don't need statements that create buzz on this topic, we need long-term action."

British Prime Minister David Cameron, campaigning against the Brexit, was accused of scaremongering when he warned in February that it could mean British border checks being removed from Calais.

"There would be nothing to stop thousands of people crossing the Channel overnight," he said then.

But for now, at least, the French government has no plans to renegotiate the treaty, which has a two-year delay written into it.

Foreign Minister Jean-Marc Ayrault warned against hasty pronouncements.

"If the border is moved to the other side of the Channel, as some suggest, we'll have to put out boats to rescue people who will be in the water," Ayrault told AFP.

"They should think before talking rubbish. People should be responsible, not engage in demagoguery."

Many migrants are already turning to flimsy dinghies in efforts to reach Britain, frustrated by tighter security around the Channel tunnel.

After authorities began dismantling Calais's infamous "Jungle" camp in March -- though up to 5,000 remain -- many others have begun trying their luck from ports along the Normandy coast.

Political scientist Francois Gemenne said London was using the Le Touquet accord to "shirk its responsibilities".

"Now that Britain is no longer in the EU, there's no reason for the border to still be in Calais," he told AFP. The accord is "unfair for France as well as for the migrants," he said.

Gemenne, a professor at the Science Po institute in Paris, mused over "the paradox... that while the vote for Brexit was mainly an anti-immigration vote, Britain may find itself having to take in more migrants."

Notably, he said, London would no longer be allowed to return asylum seekers to their first EU port of call under a different accord, the EU's Dublin agreement.

Migration expert Henri Labayle noted: "Up until now the British could claim a certain European solidarity, but that will no longer be possible."

The bilateral accord "is very costly in political terms (because) populist parties feed off of this situation," said Labayle, a professor at Pau University in southwestern France.

- 'Signal to traffickers' -

Cazeneuve has pressed for a greater financial contribution from Britain to help secure the border at Calais, notably at the city's cross-Channel ferry port.

He also warned in March that talk of scrapping the Le Touquet treaty would "send a signal to human traffickers that they can legitimately bring all the migrants to the border".

In that case, soon "it will no longer be 6,000 but 20,000" migrants massed in northern France, he warned.

Calais Mayor Natacha Bouchart is pressing for a "renegotiation" of the Le Touquet accord that would call for a migrant camp to be built in Britain.

"The history of this border is not as simple as people like to think," she said. "People shouldn't be led to believe that our problems will be solved by moving the border."