Some 1,194 migrants arrived in the UK after crossing the Channel in small boats on Saturday, a record for this year according to AFP counting from government data.
It brings the overall number of migrant crossings this year to 14,808, an unprecedented figure despite several measures in place by the French and UK governments to curb the crossings.
French coastal authorities said they also rescued nearly 200 migrants between late Friday and late Saturday.
The latest crossings, which UK Defense Secretary John Healey described as "shocking", fall short of the all-time record of 1,300 migrants arriving on small boats in a day in September 2022.
But they will still prove a headache for UK Prime Minister Keir Starmer, who has been at pains to toughen his rhetoric on irregular immigration amid pressure from the far right to slash migrant numbers.
"We all want to end dangerous small boat crossings, which threaten lives and undermine our border security," the Home Office said in a statement on the latest arrivals.
Starmer unveiled tough new immigration policies this month that include doubling the length of time before migrants can qualify for settlement in the country and new powers to deport foreign criminals.
The raft of measures was widely seen as an attempt to win back support from voters and fend off threats from the increasingly popular hard-right Reform party.
Separate legislation to tackle irregular immigration, called the Border Security, Asylum and Immigration Bill, is currently going through parliament.
But Saturday's crossings will be a fresh blow.
The overall figure of 14,808 crossings is the highest for the first five months of the year since records began in 2018, when the route into the UK first became popular.
It also surpassed the record for the number of crossings in the first six months of the year -- which stood at around 12,900 in the first six months of 2024.
'Shocking'
On Saturday, a total 184 people were picked up in four different rescue operations on the French coast, the maritime prefecture for France's Channel and northern region said in a statement.
In one instance, the motor died on a boat carrying 61 people. In another, nine people on a boat called for assistance.
According to an AFP tally of official figures, 15 people have died so far this year trying to cross the Channel, one of the busiest areas in the world for shipping.
"Pretty shocking, those scenes yesterday," Healey told Sky News in an interview Sunday.
"We saw the smugglers launching elsewhere and coming around like a taxi to pick them up," he said, adding that "Britain's lost control of its borders".
France this year agreed to allow its police patrols to intercept migrants in shallow waters, but they cannot stop a boat once it is on its way.
"We've got the agreement (with the French) that they will change the way they work," Healey said.
"Our concentration now is to push them to get that into operation."
Healey also told the BBC: "What we now need is to work more closely with the French to persuade them to put that into operation so they can intervene in the water, in the shallow waters, which they don't at the moment."
