Some 430 migrants illegally crossed the English Channel on Monday, Britain's government has confirmed.
According to the PA news agency, the figure represents a new single-day record.
Dan O'Mahoney, Britain's clandestine channel threat commander, said in a statement that "there is an unacceptable rise in dangerous small boat crossings across the channel because of a surge in illegal migration across Europe."
"People should claim asylum in the first safe country they reach and not risk their lives making these dangerous crossings. We are continuing to pursue the criminals behind these illegal crossings," he added.
The Home Office said that collaboration with the French authorities has prevented over 7,000 people so far this year from attempting the crossing — a particular dangerous endeavour as the Channel is one of the busiest shipping lanes in the world.
Still, the number of people attempting the perilous journey continues to increase.
In the first six months of the year, 7,999 migrants attempted or successfully crossed the Channel in 399 separate "incidents", according to the French Maritime Prefecture.
In 2020, the prefecture recorded 868 incidents involving 9,551 migrants — more than four times the 2,294 migrants who attempted or successfully crossed the Channel in 2019.
The UK is hoping to crack down on illegal crossings with a National and Borders Bill, currently making its way through Parliament. If backed by lawmakers, it will become a criminal offence to knowingly arrive in the UK illegally without permission and will increase prison sentences for those who attempt to enter the country illegally to four years.
It also plans for asylum seekers to be sent to "safe third countries" to make their claims.
The bill has been criticised by NGOs, including the Joint Council for the Welfare of Immigrants, which said that it represents a "fundamental challenge to the principle of refugee protection in the UK" while the tougher sentences will "further criminalise asylum seekers for exercising their legal right to seek asylum."
The organisation also argued that it is "founded on third-country deals which do not currently exist" and that "significantly curtail the rights of refugees".
The UN Refugee Agency, UNHCR, has also warned that "at the heart of the Plan is a discriminatory two-tiered approach to asylum" with access to asylum and protections severely restricted for those arriving to the UK through non-legal channels.
"This includes those arriving by boat. For the right to seek and enjoy asylum does not depend on the regularity of arrival of an asylum-seeker to a country. In reality, asylum seekers are often forced to arrive at or enter a territory without prior authorisation," it added.