Almost 900 migrants crossed the English Channel on Tuesday - a record for a single day in 2024.
Some 882 people were detected making the perilous journey from France, according to the Home Office.
It is a further blow to Rishi Sunak’s general election campaign after he made tackling the small boats crisis one of his five pledges when he became Prime Minister.
The number of migrants arriving in the UK in small boats this year now stands at a provisional total of 12,313.
This is 18 per cent higher than the total at the same point last year, which was 10,472 people. It is also 5 per cent higher than the total at this stage in 2022.
Some 15 boats were detected on Tuesday, which suggests an average of around 59 people per vessel.
There were 29,437 arrivals across the whole of 2023, down 36% on a record 45,774 arrivals in 2022.
Immigration, both legal and illegal, has been a talking point of the general election campaign, and the "stop the boats" phrase has been central in Mr Sunak's leadership.
Under pressure from the Tory right on the issue, the Conservatives have promised a "relentless" process of removing people to Rwanda until Channel crossings end.
The party’s manifesto stopped short of saying the UK could leave the European Convention on Human Rights (ECHR), despite calls from some on the right of the party, including former home secretary Suella Braverman.
Labour meanwhile has pledged to scrap the multimillion-pound stalled plan to send migrants to Rwanda and use the money to pay for a new security border command.
If elected it has pledged to launch the unit with "hundreds of new specialist investigators", vowing to "use counter-terror powers to smash criminal boat gangs" in a bid to curb Channel crossings.
Labour stated its commitment to international legal conventions, with its manifesto saying: "Britain will unequivocally remain a member of the European Convention on Human Rights.
