NORTHWOOD, England — British Prime Minister Keir Starmer and France’s Emmanuel Macron unveiled a highly-anticipated “one in, one out” pilot program to tackle illegal migration on the final day of French president’s visit to the United Kingdom.

At a joint press conference Thursday, the British leader said that the “groundbreaking” effort would see the U.K. return migrants to France that have illegally crossed the English Channel. In exchange for each returned migrant, France will transfer one asylum seeker to the U.K who would be expected to have a family connection or genuine reason to seek sanctuary in Britain.

French border forces will also be able to take proactive measures to stop boats in shallow waters, subject to a review by the French maritime authorities. 

“We simply can’t solve a challenge like this by acting alone, and telling our allies that we won’t play ball,” Starmer said.

The prime minister said the plan would “break the model” of people smuggling despite the relatively modest scale of the program, while Macron said he believed it would deter would-be smugglers and migrants seeking to make the perilous journey.

It is not known how many would be returned under the program, but initial reports have suggested around 50 migrants could be sent each way per week — only a fraction of the 21,000 who have arrived via the Channel so far this year.

Still, the U.K. prime minister pledged “hard-headed, aggressive action on all fronts, to break the gangs’ business, secure our borders and show that attempting to reach the U.K. will end in detention.”

Domestic pressure

Starmer is under acute pressure to reduce levels of illegal migration, having promised to “smash the gangs” when he came to power last year, and with Nigel Farage’s right-wing populist Reform UK party on the rise. When asked about whether the pilot program spearheaded by the two centrist leaders was ambitious enough, Starmer took a direct dig at Farage, saying he had been “working hard” to get an agreement “while others have been taking pictures of the problem.”

Though the issue of cross-Channel migration is less politically sensitive for Macron than Starmer, the French president agreed that the arrival of the so-called small boats was “an essential issue” for both countries and vowed to reinforce efforts “on several fronts.”

Macron, however, warned that the agreement over pilot scheme would be signed after judicial checks had been done, including with the European Union, and argued Brexit had in fact made illegal crossings more attractive for migrants, despite Brexiteers promising otherwise.

The press conference marked the conclusion of Macron’s state visit this week, during which the two leaders repeatedly went to great lengths to stress their personal friendship as well as the historical ties between their two countries.

The two leaders also confirmed their refresh of the Lancaster House treaties and unveiled what they called the Northwood Declaration, under which they will be able to coordinate their nuclear deterrents. They also announced a new “multinational force Ukraine” based in Paris “to support a peace deal when it comes while Putin turns his back on peace.”

The two leaders said their countries would also strengthen collaboration on supercomputers, satellite connectivity and work on seizing the opportunities offered by artificial intelligence.