A British cabinet minister on Tuesday vowed "more radical" policies to counter illegal migration as record numbers make the treacherous crossing of the Channel in small boats.

"We... now need to look at some more radical options to ensure that our laws are appropriate, that economic migrants are returned swiftly and that we deter people from coming to the UK," immigration minister Robert Jenrick told BBC radio.

"The United Kingdom cannot continue to be a magnet for economic migrants," he added.

Around 40,000 people have made the dangerous crossing across the Channel from mainland Europe so far this year, according to UK government figures.

Under-fire Home Secretary Suella Braverman has been heavily criticised for describing as an "invasion" the numbers of asylum seekers arriving on England's south coast.

But Jenrick defended her on Tuesday.

"'Invasion' is a way of describing the sheer scale of the challenge," he told Sky News.

"It is leading to the infrastructure that we have in terms of reception centres, like Manston, in terms of hotel accommodation, and asylum and social housing, essentially being overwhelmed."

Jenrick accepted that conditions at the Manston migrant processing centre in Kent, southeast England, were "poor", and that people had been sleeping on the floor on mats.

"The problem is that thousands of people are crossing the Channel illegally every day," he added.

Braverman said on Monday that the government was spending £6.8 million ($7.8 million) per day on housing migrants.

She denied claims in parliament that she "ignored legal advice" on using hotels to relieve pressure on the overcrowded processing centre.

"What I have refused to do is to prematurely release thousands of people into local communities without having anywhere for them to stay," she told MPs.

Another migrant centre was fire-bombed on Sunday by a 66-year-old man said to be suffering mental ill-health, who then killed himself.

The incident caused minor injuries to staff and was not being treated as terrorism related, Braverman said.

Braverman is also under pressure after admitting she used her personal phone to consult official documents six times.

The right-winger, whose brief includes policing and domestic intelligence, has been under mounting pressure since Prime Minister Rishi Sunak controversially reinstated her to the cabinet on taking office last week.

Braverman defended her record in parliament for the first time since being forced out by Sunak's short-lived predecessor Liz Truss.