Nearly 700 asylum seekers crossed the English Channel in a single day - a record for the year so far.
Some 696 people made the journey in 14 boats on Monday, the Ministry of Defence revealed. The previous highest number was 651 recorded on April 13.
Large groups of migrants, including young children, were seen being brought ashore this week in Ramsgate before leaving the Kent port on double-decker buses.
More than 17,000 people have arrived in the UK after navigating busy shipping lanes from France in small boats such as dinghies in 2022, according to Government figures.
Numbers are on course to hit a record high this year.
The revelation is a fresh blow to beleaguered Home Secretary Priti Patel, who has repeatedly vowed to curb numbers of migrants making the perilous journey through the Dover Strait on small inflatables.
Charities urged ministers to focus on safe routes for asylum seekers instead of "deluded deterrents".
She is braced for the sack when Boris Johnson ’s successor as Prime Minister is announced next month.
Some 3,683 migrants made the crossing on 90 boats in July, the highest monthly total this year,
Journeys are believed to have taken place on 20 out of 31 days last month.
It is more than three months since Ms Patel unveiled plans to send migrants to Rwanda to try to deter people from crossing the Channel.
Since then 11,827 have arrived in the UK after completing the voyage.
On April 14 Ms Patel signed what she described as a "world-first" agreement with Rwanda for the east African nation to receive migrants deemed by the UK to have arrived "illegally" and are therefore inadmissible under new immigration rules.
But the first deportation flight, due to take off on June 14, was grounded amid legal challenges.
Several asylum seekers, the Public and Commercial Services union and charities Care4Calais, Detention Action and Asylum Aid are challenging the legality of the Home Office policy.
The next court hearings are due in September and October.
Charities urged the Government to find ways for asylum seekers to reach Britain legally without having to board inflatables in northern France.
Safe Passage International chief executive Beth Gardiner-Smith said: “We’ve warned time and time again of the dangers of not having safe routes to the UK – loss of life and more people desperately crossing the Channel – but the Government has repeatedly ignored our warnings.
“Despite cruel threats to banish refugees to Rwanda, people in need of safety are continuing to risk their lives across the Channel because there is no other way to reach sanctuary.
“Instead of dreaming up deluded deterrents, the Government must do what works and open safe routes to the UK for refugees.
“No one should have to risk their life to seek safety.”
A Government spokesman said: “The rise in dangerous Channel crossings is unacceptable.
“People should always claim asylum in the first safe country they reach, rather than risk their lives and line the pockets of ruthless criminal gangs in order to cross the Channel.
“The New Plan for Immigration is reforming the UK’s broken asylum system.
“The Nationality and Borders Act makes it a criminal offence to knowingly arrive in the UK illegally and we have introduced life sentences for those who facilitate illegal entry into the country.
“Since the introduction of the act, 23 people have been arrested.
“Under our new Migration and Economic Development Partnership with Rwanda, we are continuing preparations to relocate those who are making dangerous, unnecessary and illegal journeys into the UK in order for their claims to be considered, for them to be able to rebuild their lives and deter others from making life threatening crossings.”
