The UK-French “one-in, one-out” pilot scheme, aimed at reducing the number of small boats crossing the Channel, has come into force with detentions of illegal migrants due to start within days.
The deal will see some of those arriving in the UK in small boats detained and returned to France.
In exchange the UK will accept from France an equal number of asylum seekers provided they have not already tried to make the crossing and can pass security and eligibility checks.
Prime Minister Sir Keir Starmer said the plan was a “product of months of grown-up diplomacy” which would “deliver real results”.
But the Conservatives said it would “make no difference whatsoever”.
Sir Keir and French President Emmanuel Macron announced the agreement in July, but it was still subject to legal scrutiny by the European Commission and EU member states.
The UK government has now said that the “EU Commission, Germany and other member states have given the green light on this innovative approach” meaning the scheme can go ahead.
Under the plan, an adult migrant who tries to get to the UK by crossing the Channel could be returned to France if their claim for asylum is deemed to be inadmissible. Returns could begin to take place within weeks.
UK and international law prevents the government from sending asylum seekers back to their country of origin before their claim has been considered and turned down. However, they can be sent to safe countries prepared to consider their claim.
The government has not confirmed how many migrants would be returned and accepted under the plan, but said it would look to “ramp up both the pace and scale of returns over the course of the pilot scheme”.
There have been reports that 50 people per week could be returned, compared to the weekly average of more than 800 people currently making the crossing.
Sir Keir has previously said the pilot is not “a silver bullet” but believes it will deter people from making the dangerous journey following a big increase in the numbers so far this year.
As of 30 July, more than 25,000 people had crossed the Channel in small boats in 2025 – around 49% higher than at the same point in 2024.
The government is under pressure to reduce the numbers, having previously promised to “smash the gangs” organising the journeys.
Home Secretary Yvette Cooper hailed the agreement as “ground breaking” and an “important step towards undermining the business model of the organised crime gangs”.
“It is also right to make clear that – while the UK will always be ready to play its part alongside other countries in helping those fleeing persecution and conflict – this must be done in a controlled and managed legal way, not through dangerous, illegal, and uncontrolled routes,” she said.
On Monday, the government announced £100m to fund 300 National Crime Agency Officers to stop the people smugglers arranging the crossings.
It has also said it wants to tackle illegal working, to reduce pull factors encouraging people to come to the UK.
Conservative shadow home secretary Chris Philp said the government’s deal with the French would be less effective than the Rwanda plan, proposed by the previous Conservative government.
“The Rwanda removals deterrent, under which 100% of illegal arrivals would be removed, was ready to go last summer but Labour cancelled it just days before it was due to start with no proper replacement plan,” he said.
“As a result, this year so far has been the worst ever for illegal immigrants crossing the Channel.”
When the UK and France first announced the plan in July, the charity Asylum Matters criticised the measure, arguing: “The only way to stop people from making dangerous journeys is to give them real safe routes to seek sanctuary.”