Britain will meanwhile provide up to £664 million in funding -- though nearly a quarter of that will be conditional.
The cross-Channel neighbours have wrangled for months over renewing the Sandhurst treaty, which sets out the UK's financial contribution to French efforts to stop migrants attempting the perilous sea crossing to Britain.
The UK has accused France of doing too little to prevent would-be asylum seekers from setting off from French shores, with smugglers and migrants taking ever-greater risks to avoid detection.
As a result, London insisted it would only renew the Sandhurst treaty -- first signed in 2018, extended in 2023 and set to expire this year -- if it could impose conditions on how British money is used by the French government.
Prime minister Keir Starmer said Annglo-French work 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".
According to a French home ministry document on the accord, if the new measures do not deliver "sufficient results, based on a joint annual assessment, the funding will be redirected to new actions".
Even if the conditional portion is not paid, however, the UK's core contribution of £502m still represents a £34.7m hike on what it paid under the last treaty.
French home minister Laurent Nunez and his UK counterpart Shabana Mahmood are to lay out further details of the plan on Thursday (23) while visiting the site of a proposed accommodation centre for people to be deported from France at Loon-Plage, near Dunkirk.
"This landmark deal will stop illegal migrants making the perilous journey and put people smugglers behind bars," said Mahmood.
The deal's renewal comes at a crunch time for Starmer, who faces political pressure to curb immigration.
The centre-left leader is also engulfed in an unrelenting scandal over the appointment of Peter Mandelson as ambassador to the US despite his friendship with the late convicted sex offender Jeffrey Epstein.
Shabana Mahmood arrives ahead of the weekly cabinet meeting at Downing Street on March 17, 2026 in London, England. (Photo by Dan Kitwood/Getty Images)
Many believe Starmer's political survival depends on his Labour party's performance in local electiions in May. Polls indicate that it faces major losses.
Besides the step-up in law enforcement on the beaches, France is looking to deploy drones, helicopters and digital resources to prevent crossings, the roadmap said.
By the terms of the international law of the sea, once a boat has set off from shore, the authorities can only intervene to save people from drowning.
According to official British figures, 41,472 people reached the UK illegally in small boats in 2025, the second-highest figure since large-scale crossings were first detected in 2018.
At least 29 migrants died at sea in the Channel in 2025, according to an AFP tally based on official French and British sources.
France has pointed to the fact that since the beginning of 2026, arrivals to the UK have halved compared with the same period last year. Around 480 smugglers were also arrested in 2025, according to the French home ministry.
(AFP)
