PARIS — Britain and France are set to unveil a new multimillion-euro deal Thursday aimed at reducing the number of migrants crossing the English Channel in small boats, with increased police patrols and enhanced surveillance in northern France.

Home Secretary Shabana Mahmood and French Interior Minister Laurent Nunez are to sign the three-year agreement during a joint visit to the region.

Under the deal, the U.K. will provide 500 million pounds ($675 million) to strengthen measures in northern France, with an additional 160 million pounds ($216 million) depending on the success of new tactics to curb Channel crossings. If those efforts fail, the additional funding will be halted after one year, the Home Office said.

The agreement provides for boosting the number of officers deployed on the ground from 907 now to 1,392 for the 2026—2029 period, along with the creation of an additional police unit dedicated to combating irregular migration, funded by France, the French Interior Ministry said.

It will also include the deployment of new technologies aimed at reducing departures of so-called “taxi boats,” the term authorities use for small motorized vessels, usually inflatable, used by smugglers to pick up migrants along long stretches of the northern French coast.

Unlike boats that migrants carry into the water themselves, “taxi boats” typically set off largely empty from secluded coastal areas and pick up migrants at prearranged meeting points on beaches.

The deal also expands surveillance capabilities through drones, helicopters and electronic monitoring, to better prevent crossing attempts.

U.K. Prime Minister Keir Starmer said cooperation between the two countries had “already stopped tens of thousands of crossings” and that “this historic agreement means we can go further — ramping up intelligence, surveillance and boots on the ground to protect Britain’s borders.”

So far this year, arrivals in the U.K. have fallen by more than half compared with the same period in 2025, according to the French interior ministry. Police operations led to the arrest of 480 smugglers last year, it said.

A large share of the resources provided under the deal will be deployed from early summer, traditionally the busiest period for crossing attempts as weather conditions improve.

Earlier this month, two men and two women died as they were trying to board an inflatable boat off the coast of northern France. British authorities arrested a man from Sudan on Friday on suspicion of endangering life in that case.

The new agreement builds on the Sandhurst Treaty, first signed in 2018 and renewed in 2023.