The UK will pay France £8m more a year under a revised deal to try to stop people crossing the English Channel in small boats.
Under the updated agreement, UK police officers will be embedded with their French counterparts in control rooms and on beaches.
The number of officers patrolling the French coast to try to stop people setting off will rise from 200 to 300.
PM Rishi Sunak said he was “confident we can bring the numbers down”.
But, speaking to reporters whilst travelling to the G20 summit in Bali, he warned there was no “single thing” that could be done to “fix” the situation.
The government is under increasing pressure over Channel crossings, with the number of people making the journey rising to record levels.
More than 40,000 people have crossed in small boats so far this year, up from 28,526 last year and 8,404 the year before.
Over the weekend, some 853 people were detected crossing the English Channel in small boats on Sunday, following 972 crossings on Saturday, the Ministry of Defence said.
Under the new agreement, signed by Home Secretary Suella Braverman during a trip to Paris, the amount the UK pays France to cover the cost of increased patrols will increase from £55m last year to £63m this year.
During her visit, Ms Braverman told UK broadcasters the money would pay for a “40% uplift” in the number of French police patrolling French beaches.
As well as extra officers and patrols, the British money will allow more use of drones and night vision equipment, and will also be spent on boosting reception and removal centres in France.
French ports will receive investment to increase the use of CCTV and detection dog teams to prevent illegal entry to the UK via lorries. UK observers will be embedded in French control rooms, and French observers embedded in UK control rooms – to help inform each other’s deployments.
Last month, the Home Affairs Committee heard that the UK is spending almost £7m a day on hotels for asylum seekers.
MPs also heard that only 4% of asylum claims by migrants who crossed the English Channel in 2021 had been processed.
Ms Braverman has previously admitted the system was “broken” and Mr Sunak has said not enough asylum claims were being processed.