More people crossed the Channel in small boats on Monday than any day since records began.
The total of 1,295 is the highest recorded, the Ministry of Defence confirmed.
Some 27 boats made the journey, news which is likely to put pressure on the Tory leadership candidates to set out how they will tackle the trade.
More than 22,600 people have arrived in the UK after navigating busy shipping lanes in small boats since the start of the year.
People trafficking gangs capitalise on calm weather in the summer to launch several boats in quick succession.
The crossings came after a three-day hiatus between Friday and Sunday when no arrivals were recorded.