Nigel Farage, one of the leading voices in Britain’s campaign to leave the EU, on Monday urged the government to declare an "emergency" over the surge in migrant crossings of the Channel to the UK.
More than 235 migrants made the perilous journey to the UK on Thursday in a surge Home Secretary Priti Patel called appalling.
Then 146 more arrived on Friday and 150 on Saturday.
More than 650 migrants have arrived so far in August, including babies and unaccompanied children.
The increase in arrivals is thought to be caused by the warm and sunny weather, during which the journey on the world’s busiest shipping lane is less dangerous.
Over the weekend, the British government appointed a former Royal Marine commando to try to stop people crossing in small boats.
Ms Patel said Dan O‘Mahoney would work with French authorities on stronger enforcement, including intercepting boats at sea.
In a column for The Telegraph newspaper on Monday, Mr Farage criticised the government for not taking enough action to stop crossings and called it a national humiliation.
“Of all the reasons for voting Brexit in 2016, the desire for Britain to control its borders properly was the single thing that increased turnout at the referendum and resulted in the Leave vote,” the Brexit Party founder wrote.
Mr Farage said that although a Brexit deal by the end of the year might make 2020 the last year that Channel crossings are possible, the UK could not afford to wait until January next year to crack down on migrants.
“The time has come already to declare an emergency,” he said.
“This would be far better than sending a few Royal Navy vessels into the Channel where, as things stand, they would simply join the Border Force and RNLI in becoming a taxi service.”
Mr Farage’s comments have been criticised by some MPs, who regard them as divisive and fear-mongering.
Earlier on Monday, British Prime Minister Boris Johnson was accused by charities of making migrants scapegoats and using “inaccurate and inflammatory language” to describe their plight.
Humanitarian groups and charities criticised Mr Johnson for describing the migrant crossings as “very bad and stupid, and dangerous and criminal”.
Stephen Hale, chief executive of Refugee Action, said the people crossing the sea to Britain were a tiny part of a global refugee crisis.
“This is serious for the people concerned, but it’s a modest movement by international standards and it’s certainly something that Britain can cope with,” Mr Hale said.
He compared the situation with that of Lebanon, which has taken in 1.5 million Syrian refugees.
Many of the migrants trying to reach Britain come from Afghanistan, Iraq, Syria and countries in Africa, fleeing poverty, persecution or war.