The UK will give France almost £500m over three years to help stop migrants crossings the Channel in small boats.
The cash was announced at a summit in Paris between UK Prime Minister Rishi Sunak and President Emmanuel Macron, who said France will also contribute.
The money will go towards setting up a new detention centre in France and boosting patrols on French beaches.
The UK had planned to pay France around £63m this year to tackle the problem.
The new package appears to at least double that amount, with the UK pledging £120m in 2023-24.
France will contribute substantially more funding to the project, however there are not yet details about the overall sum.
Labour’s shadow attorney general Emily Thornberry accused the Conservatives of “lurching from one crisis to another with nothing more than their typical sticking plaster politics”.
“Before Rishi Sunak sends even more money to the French authorities to tackle this crisis, he needs to explain what was achieved by the hundreds of millions we’ve given them before, and why small boat crossings continued to go up regardless.”
French President Emmanuel Macron praised the joint efforts of UK and French teams working to reduce small boat crossings.
Speaking at a press conference with Mr Sunak at the Elysee Palace, he said the team had prevented 30,000 small boat crossings and made 500 arrests in the past year.
Mr Sunak said the money would help “put an end to this disgusting trade in human life”.
He added: “Working together, the UK and France will ensure that nobody can exploit our systems with impunity.”
Both men said the summit in Paris marked a new beginning in Anglo-French relations. (BBC)