The UK will pay France an extra £16.2m to keep police patrolling Channel beaches and prevent a surge in small-boat crossings after negotiators failed to agree a permanent deal before a midnight deadline.

The stopgap arrangement, which will last for two months, comes after French negotiators refused to agree to UK demands for further interventions and patrols to stop asylum seekers from reaching the UK via the Channel.

It is understood the French government also refused to guarantee that patrols would continue without extra funds.

Signed off by the home secretary, Shabana Mahmood, the temporary deal comes after a deadlock over plans to revamp the three-year, £478m deal, due to lapse at midnight on Tuesday.

Home Office negotiators had insisted on a “huge surge” of extra officers under a new agreement, as well as a guarantee of an increase in the number of small-boat interventions by French officials as they sought to disrupt gang activity.

Paris is concerned that UK demands could put the lives of asylum seekers and French officers at greater risk.

The development is the latest twist in the discussions between the two governments over how to halt unauthorised small-boat journeys, and who should pick up the majority of expenses.

A Home Office spokesperson said: “The home secretary is driving a hard bargain with the French to deliver the best deal for the British people, prevent migrants boarding boats and to save lives. We want more bang for our buck.

“We don’t want there to be a surge in migrant crossings while negotiations continue. We are looking for a significant surge in enforcement officers on French beaches.”

At present, the UK pays nearly two-thirds of the annual cost of patrols in northern France. Mahmood is seeking to link the next three years of funding to an increase in small-boat interceptions. She also wants more regular information on how many interventions have been made.

The Guardian has asked the Home Office how much France will contribute in additional expenses over the stopgap period.

Nigel Farage, the leader of Reform UK, said he would end any deal with France. At a press conference at Heathrow on Tuesday, he said: “Tomorrow will be a very busy day in the English Channel, and it wouldn’t make any difference whether we agreed to a further £365m or not. Even if the French do stop boats from crossing, the same people come back the next time there is a calm day, and it’s all about pull factors, it’s all about the fact you’ve got a 97.5% chance, whoever you are, of staying in the United Kingdom if you illegally cross the Channel in a small boat.”

Home Office sources responded by saying the money spent on French patrols was vital to stopping much larger numbers of people coming to the UK.

A source close to Mahmood said: “These comments are completely reckless. Ultimately, does Nigel Farage really want 42,000 more migrants coming to Britain? Because that’s the cost since the election that the deal has presented.

“We obviously want to go further and make it a more efficient and better deal so we can stop even more illegal migrants crossing.”

In the negotiations, the UK is demanding a firmer agreement on France’s use of a new maritime law enabling authorities to intercept boats at sea.

The talks to renew the patrol deal are separate to negotiations to renew the “one in, one out” migrant returns deal with France, which expires in June.

Xavier Ducept, France’s junior minister for the sea, has criticised the UK for making demands that risk the lives of asylum seekers.

He told a French parliamentary commission of inquiry last week: “What we want is for … the British to contribute to funding interception systems, which are very expensive. But they must not make this funding conditional on a type of efficiency that could be extremely dangerous for migrants, for the [security] services, and for France … rescue comes first. And the law.”

Nearly 700 officers from units dedicated to intercepting small boats will continue to patrol the French coastline. Surveillance and vehicles, including vans and dune buggies, will continue to identify and intercept launches.

The then Tory government announced the £478m package in 2023, saying it would fund a new detention centre in France and hundreds of extra law enforcement officers on French shores.

Since then, the number of crossings has increased, with 41,472 people arriving in the UK by small boat in 2025.