The number set a new single-day record, surpassing the previous daily high of 416 set in September of last year, according to data compiled by the PA news agency.
Monday’s figure included a group of around 50 men, women and children who were seen marching ashore after landing near Dungeness in Kent.
They are believed to have left northern France or Belgium on a dinghy earlier on Monday.
The dinghy was monitored by the RNLI as it approached the coast before landing at around 1:00 p.m.
After the group arrived, some of its members celebrated, while others sat on the beach.
It came as Parliament debated proposals to reform Britain’s asylum system.
Former Prime Minister Theresa May has warned against sending asylum seekers to offshore processing centers, which is being done under controversial policies in Australia.
Ms May said she had already considered the idea but had not taken it further due to “practical concerns”.
The Nationality and Borders Bill could see asylum seekers sent to a “safe third country” where they would submit their claims at a “designated place” determined by the secretary of state.
Bella Sankey, director of the Detention Action charity, said: “The Home Office’s anti-refugee bill is political theater that does not even pretend to address the problem or make our system safe, fair or efficient. .
“We need a mechanism whereby refugees arriving at the British border in France have a safe passage, and until we do, everything else is noise and distraction. “
So far, more than 1,850 people have reached Britain on small boats in July, according to the AP analysis.
This is more than the total for 2019.