London: French President Emmanuel Macron is trying to arm-twist the UK government into accepting more refugees to help clear out Calais' notorious migrant camps - and Brexit is his ace in the hole.
In a key speech on migration in Calais on Tuesday, Macron said the interests of the Calais region "will be fully taken into consideration" when preparing France's position on Brexit and on any potential future trade and customs deal with the UK.
Though he was explicitly referring to fishing, logistics and industry sectors, one of the region's biggest issues is that it has become a bottleneck for migrants from places such as Afghanistan and East Africa wishing to cross the Channel.
New concessions won by Macron may be announced at a summit on Thursday with British Prime Minister Theresa May at the Sandhurst military academy.
The Times newspaper reported a source "at the French presidency" claiming May had "bowed to pressure" from Macron to put migration on the summit agenda, and the French were pushing her to agree to a taskforce to pick up unaccompanied migrant children from the Calais area and accelerate their transfer across the Channel.
There have been ugly clashes between police and migrants around Calais. Macron used his speech to denounce the use of tear gas and physical violence against migrants, saying no breaches of professional ethics by police would be tolerated.
"Calais is a land of passage, which has become a dead end for thousands of women and men who have spent years on the road," Macron said.
He said France's "duty is to protect those who are persecuted and are seeking asylum".
"A person who flees a country at war should not have to face roads of misery, and sometimes the violence of slavery," he said.
However there was also a duty to "protect the Republic," he said.
"Everyone needs to know [that] everything is being done to prevent the illegal passage [of migrants] to Britain," Macron said.
Visiting a migrant reception centre near Calais, he told refugees and local officials that in France "it's impossible to integrate millions and millions of people, but we have this duty to protect people when they are at risk".
Macron has taken a tough line on what he calls "economic migrants", with a new immigration bill to be debated this year aimed at speeding up the handling of asylum applications and the expulsion of those whose claims are rejected.
Macron's stance has split his government and party.
On Tuesday, a group of intellectuals and trade unionists - including Jean Pisani-Ferry, who wrote Macron's election policy on the economy - published a letter in Le Monde saying Macron's migration policies "contradict the humanism that you propose".
Under Macron, France was "a country that is snatching blankets from migrants in Calais. Where people are lacing up their tents on the streets of Paris. Where people are getting lost, their hands and feet frozen, on the snowy slopes of the French-Italian border," the letter said.
"Eritreans, Sudanese and Syrians, humiliated in their country, tortured in Libya, exploited by criminal traffickers, terrorised on the Mediterranean, who entered Europe through Greece or Italy, could soon be deprived of liberty in France."
They said if Macron did not live up to his ideals he would add to a "stone wall of moral indifference that grows everywhere on our continent".
Macron has a strong negotiating position at the Sandhurst summit - he would prove a vital ally for May in this year's Brexit trade talks. And he may also threaten to withdraw from the Le Touquet treaty, under which Britain is allowed to run border checks on French territory, effectively moving its border across the Channel and keeping unwanted migrants off British soil.
Macron is also expected to push for more money and resources from Britain to deal with the migrant flow into Calais.
"In no case will we allow another Jungle to be established in Calais," he said in his Tuesday speech.
Macron's predecessor Francois Hollande ordered the dismantling of the notorious, unsanitary and unsafe Jungle camp in October 2016, moving its then 7000 inhabitants into official accommodation.
But around 500-700 migrants continue to camp out in the town's margins, trying to stow away on trucks bound for Britain.
Last year, migrants made 115,000 attempts to cross the Channel, according to a French presidency source quoted in the Times. This was 50,000 fewer than the year before.
Whitehall has yet to show its cards in advance of the UK-France summit, however Fairfax Media understands the UK government is opposed to an end or re-negotiation of the Le Touquet agreement, arguing that it is in the interests of both countries, and that Britain has already provided significant help in beefing up security at Calais.
The summit will include discussions on the 50-year defence and security treaty between the two countries signed in 2010.
Looking towards Brexit, the UK government also wants to expand conversations beyond defence.
