A record-breaking number of 853 crossed the in small boats on a single day this week, the UK's interior ministry said Friday.
The said that UK authorities had rescued or intercepted at least 853 migrants in 25 separate incidents on Wednesday.
This exceeded the previous highest figure of 828 set in late August and is the highest number since the crisis began.
The past three years have seen a significant rise in attempted Channel crossings by migrants, despite warnings of the dangers in the busy shipping lane between northern France and southern England, which is subject to strong currents and low temperatures.
According to a count by Britain's domestic news agency PA, more than 21,000 migrants have made the crossing to Britain in small boats since the beginning of the year -- more than double the figure for the whole of 2020.
Attempted crossings increased this week due to favourable weather and excellent visibility as well as migrants wanting to get over before the winter.
French authorities said that more than 400 people were rescued on Wednesday when several vessels sank in the Channel while one man drowned and another migrant was missing.
On Thursday, a migrant's body was found in a boat that washed up on the French shore near Calais with two other passengers aboard suffering from hypothermia.
The issue of policing migrants wanting to cross the Channel is a constant source of friction between France and the UK.
The UK government is pushing through new legislation that would significantly toughen penalties against such migration, and Home Secretary Priti Patel says she is reviewing maritime tactics to deter people-smugglers.