More than 35,000 people have made the journey so far in 2024, which is 20% higher than last year.
Those who arrived in Dover on 25 December broke a period of more than a week of no crossings.
The last time vessels carrying migrants were known to have made the journey was on 14 December, when 160 people in three boats arrived, according to the Home Office.
The 35,040 people to have arrived this year is fewer than the record high for a year in 2022, when 45,775 people made the crossing.
Home Secretary Yvette Cooper previously acknowledged that it would be “no comfort” to the public if numbers continued to remain at high levels.
Sir Keir Starmer said he had made “smashing the gangs” who facilitate the small boats crossings one of his top priorities.
The Prime Minister has set up a new Border Security Command, and is attempting to work more closely with the UK’s European neighbours to pull apart organised crime gangs involved in people smuggling.