People who arrived in the UK on a small boat have been detained under Keir Starmer’s “one in, one out” deal for the first time and are expected to be returned to France within three weeks, the Home Office has said.
Detentions began on Wednesday lunchtime, with those identified in the Channel boat being held in immigration removal centres pending their removal.
The UK would be expected to make referrals to France within three days, and the French authorities would be expected to respond within 14 days, officials said.
A small proportion of migrants arriving on small boats will be selected for removal to France and, in return, Britain will accept an equal number of asylum seekers from France.
Questions remain over the treaty implementing the “one in, one out” agreement, with immigration lawyers saying that its confusingly worded terms could be challenged by anyone attempting to block their return to France.
The reciprocal scheme allowing asylum seekers with links to the UK has also begun. Applicants must satisfy the eligibility and suitability criteria, including uploading a passport or other identity documents as well as a recent photograph.
Those selected will have to pass further stringent security checks and biometric controls, meaning that only those individuals whom the UK government has approved for entry will be allowed through the new route.
People from wartorn and drought-hit countries such as Eritrea could be excluded from the scheme by the requirement for official documents, a charity has warned.
A Refugee Legal Support spokesperson said: “This week in Calais, we spoke with many people from Eritrea and almost none of them have copies of their Eritrean passports because they were never able to obtain one. Eritrean nationals are the top nationality crossing the Channel in 2025; 86% of Eritrean asylum seekers receive a positive decision, but almost all will be excluded from this scheme.”
As the one-in, one-out pilot scheme continues into its implementation phase, the Home Office is also launching a campaign warning people not to risk their money or their life, to be promoted in the coming days across multiple channels.
The deal has been trumpeted by ministers as a “gamechanging” deal but Home Office sources said it would apply only to about 50 asylum seekers at first.
Yvette Cooper, the home secretary, did not confirm how many people were being prepared to be returned to France and said the government would resist any legal challenges.
“The transfers to immigration removal centres are under way as we speak, so we won’t provide operational details at this point that criminal gangs can simply use and exploit.
“But no one should be in any doubt: anyone who arrives from now on is eligible for immediate detention and return,” she said.
“It’s the beginning of the pilot and it will build as well over time, but we’re also clear that France is a safe country, so we will robustly defend against any legal challenge that people try.”
A copy of the agreement was released on Tuesday as the prime minister comes under increasing pressure to stop boats carrying asylum seekers from crossing the Channel.
The UK will pay the costs of transporting asylum seekers to and from France. The deal will have to be renewed by 11 June next year, and can be ended at a month’s notice by either side.
If people have an outstanding claim for asylum, they cannot be removed, the deal says.
France can reject a requested removal if it “considers that an individual would be a threat to public policy, internal security, public health or the international relations of any of the Schengen states”.
So far in 2025, more than 25,000 people have arrived in the UK after crossing the Channel in small boats – a record for this point in the year since data began being collected in 2018. That is up 48% on the same time last year.
