The number of migrants reaching the UK by boat was four times greater in 2020 than 2019, official figures show.
At least 8,400 people made the crossing in 2020 while last year 1,844 did.
Despite freezing temperatures, 33 migrants reached the UK in four boats on Thursday morning. Another 23 followed in the afternoon.
The totals, based on a running tally of Home Office figures, account for any migrants intercepted in the Channel or held by officials upon arrival.
As well as the 33 who made the trip in dinghies on Thursday, a further 17 were prevented from making the crossing by French authorities.
Border Force also detected 23 more people attempting to enter the UK illegally at Newhaven after travelling on an afternoon ferry from Dieppe.
Minister for immigration compliance Chris Philp said: "France is a safe country with a well-functioning asylum system.
"People should claim asylum in the first safe country they reach and not risk their lives making a dangerous and illegally-facilitated crossing.
"We continue to work closely with the French following our agreement to take further action to tackle illegal migration, through increasing police patrols and surveillance."
The Home Office said the number of police officers on the ground in France had doubled in response to the volume of migrants attempting the crossing.