The UK will pay the costs of transporting asylum seekers to and from France under Keir Starmer’s “one in, one out” deal with Emmanuel Macron, it has emerged.

The deal will have to be renewed by 11 June next year, and can be ended at a month’s notice by either side, documents made public by the government indicate.

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 deal will allow the UK to return one person who has entered the country by irregular means in return for taking someone in France whose claim for asylum in the UK is expected to have a greater chance of success.

It has been trumpeted by ministers as a “gamechanging” deal but Home Office sources said it will only apply to about 50 asylum seekers at first.

“All transport costs incurred in connection with readmission pursuant to this agreement shall be borne by the United Kingdom,” the documents state.

They continue: “Those accepted for admittance [from France] … shall be provided by the United Kingdom with transport from a designated place to the United Kingdom (at the cost of the United Kingdom).”

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, 25,436 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.

This is up 48% on this point last year (17,170) and 70% higher than at this stage in 2023 (14,994), according to PA news agency analysis of Home Office data.

At least 10 people have died while attempting the journey this year, according to reports by French and UK authorities, but there is no official record of fatalities in the Channel.