The United Kingdom began implementing its new "one-for-one" migrant return agreement with France on Wednesday, enabling exchanges of illegal arrivals for legitimate asylum-seekers with British ties.

The European Commission-approved initiative marks the first such bilateral return arrangement between the two countries, with both sides emphasizing their role in deterring dangerous Channel crossings.

The plan marks a key initiative in UK Prime Minister Keir Starmer's strategy to combat illegal migration amid rising political pressure.

Starmer and France's President Emmanuel Macron announced the "one in, one out" agreement last month as part of wider efforts.

For each person returned under the new deal, the UK will accept an equal number of eligible migrants through legal channels, provided they meet security requirements and have not previously attempted Channel crossings.

UK government sources had said previously that the new agreement would involve about 50 returns a week, or 2,600 a year.

UK Home Secretary Yvette Cooper said on Tuesday that there are no set limits on the number of migrants to be exchanged under the new bilateral agreement.

Wider strategy

Despite criticism that the program's scale will mean it has only a limited deterrent effect, Cooper insisted the French agreement forms just one component of a wider government strategy.

Other government measures target smugglers through sanctions, tackle social media recruitment, and work with food delivery companies to prevent illegal employment, reported Reuters.

Speaking to ITV News, Cooper declined to estimate the number of migrants facing return to France.

She said: "There's no specified number agreed as part of the overall program, because we want to build it and we want to test it.

"This is a pilot program. We expect it to build over time and we want to increase the numbers, but we need to test the processes, because this has never happened before."

Speaking to Sky News, she added: "The principle says, frankly, if you arrive here on a small boat, you have paid thousands of pounds to a criminal people smuggler actually, you should be being returned, that money should be lost … and we should be taking those who have applied lawfully who've been through security checks."

France's Interior Minister Bruno Retailleau posted on X that disrupting people smuggling operations is the "clear objective" of the new agreement.

More than 25,000 people have reached the UK by small boats this year so far, despite Starmer's pledge to "smash the gangs" of smugglers and reduce arrivals.

Tensions have escalated across England as both pro — and anti-immigration groups staged protests at hotels housing asylum-seekers in recent weeks.