The prime minister remarked the deal represents a new chapter in Anglo-French relations, as Deputy Political Editor Anushka Asthana reports
Rishi Sunak has agreed to give France almost half a billion pounds to help achieve his aim of "stopping the boats", a deal Downing Street has hailed as "unprecedented".
The prime minister committed to sending Paris £478 million (€541 million) to fund a new detention centre in France and hundreds of extra French law enforcement officers.
Mr Sunak announced the package after meeting French President Emmanuel Macron during a UK-France summit at the Elysee Palace in Paris on Friday.
The PM has made stopping illegal immigration one of his top priorities and it was understood he would need cooperation from France if he was to make that a reality.
But there was no sign of the returns agreement with France that the government desires, as Mr Sunak makes “stopping the boats” one of his top priorities.
One of the great prizes of Brexit was said to be the ability for Britain to control its borders, however an unintended consequence was it left a returns agreement within the EU which allowed countries to send migrants back to the country they'd left.
Illegal entry of the UK actually surged following Brexit, with more than 45,000 people succeeding in making the Channel crossing in 2022 - a record-breaking figure.
At a joint press conference alongside Mr Macron, Mr Sunak said he was "delivering on that priority" to stop Channel crossings, with the agreement with France which comes on top of his Illegal Immigration Bill.
Mr Sunak said: “Last year I agreed the largest ever small boats deal with France to increase UK-funded patrols by 40%. This week I announced measures to ensure nobody who enters the UK illegally can remain here.
“We don’t need to manage this problem, we need to break it. And today, we have gone further than ever before to put an end to this disgusting trade in human life. Working together, the UK and France will ensure that nobody can exploit our systems with impunity.”
Earlier this week he announced new legislation to tackle migration, with a Bill which would force detention on almost everyone who enters the UK illegally, see them deported and bar them from ever returning.
Campaigners say the controversial legislation will break human rights laws if it is implemented but Mr Sunak has insisted it will not and says he's "up for the fight" if it's challenged in the courts.
The UK had already committed more than £300 million to France in the last decade to help tackle unauthorised migration.
But more than 3,000 people have already made the perilous sea journey this year.
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That is despite Mr Sunak and Home Secretary Suella Braverman announcing a £63 million package to increase patrol officers by 40% four months ago. That package followed a £55 million deal in 2021.
It is the first time the UK will contribute to building a detention centre in France to help deal with the numbers of people being trafficked.
Ministers say twice as many unauthorised crossings were stopped last year than in the previous 12 months and hope the new drones, aircraft and other surveillance technologies being funded will increase this.
On a returns agreement, Mr Macron said the UK must negotiate with the EU rather than France.
He said: “This is not an agreement between the UK and France, but an agreement between the UK and the EU. Because the Dublin agreement are no more in a situation to be implemented so this is something now to be negotiated.”