Nearly 400 migrants have been intercepted trying to cross the Channel in the past two days – as French police dismantled a Calais camp on Friday.
Border Force officials dealt with eight incidents on Thursday involving 201 people, the Home Office confirmed.
The French authorities intercepted nine boats on Wednesday and Thursday, preventing 171 people from reaching the UK.
And the Coastguard helped rescue people trying to get to the UK in a boat near Hastings in East Sussex on Thursday, a Home Office spokeswoman said.
Weather conditions over the past week have been warm and the Channel, which can sometimes be very choppy, has been relatively flat with low wind speeds, making crossings slightly easier.
The Home Office spokeswoman said: "Criminal gangs are putting profits before people's lives through these dangerous and unnecessary crossings.
"More than 3,500 people have been prevented from making the dangerous crossing so far this year and we are cracking down on the despicable criminal gangs behind people smuggling.
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"Inaction is not an option whilst people are dying.
"The government is bringing legislation forward through our New Plan for Immigration which will break the business model of these heinous people-smuggling networks and save lives."
Since the beginning of 2021, more than 3,100 migrants – double the same period in 2020 – had made the 21-mile journey across the Channel by the end of May.
The easing of coronavirus lockdown and the reopening of the European Union has seen many more migrants travelling to Calais in northern France again, hoping to reach the UK.
On Friday, French police dismantled a makeshift migrant camp in Calais, removing hundreds of people during an early morning operation.
Local authorities said the number of people had significantly increased in recent weeks.
"Several hundred migrants were identified on the premises, including about 30 children," they said.
Migrants, many having fled North Africa, the Middle East and Asia, were taken to various reception centres in the region.
Since the dismantling of the "Calais Jungle" camp in 2016, where up to 9,000 people lived, migrants are now scattered across several camps, most on the outskirts of Calais.