Six boats and a kayak carrying 80 migrants have been intercepted off the Kent coast.
The Home Office said 65 men and 15 women had crossed the English Channel on Tuesday in small boats.
A spokesman said the migrants travelled from France and were taken to Dover, where they were medically assessed.
The migrants presented themselves as Libyan, Moroccan, Iraqi, Syrian, Kuwaiti, Iranian, Afghan, Eritrean and Sudanese.
The Home Office said where appropriate immigration officials would detain some of them, while others will be sent back to France.
"These attempted crossings are reckless acts facilitated by criminals that we are determined to stop," the spokesman added.
"The crossings are often organised by dangerous criminal gangs.
"Our priority will always be arresting and dismantling the organised crime gangs behind these crossings."