The government plans to fly asylum seekers to Rwanda for processing in an attempt to tackle small boat crossings in the Channel.
Boris Johnson is set to argue action is needed to combat the “vile people smugglers” turning the ocean into a “watery graveyard” in a speech on Thursday.
After the prime minister’s speech, Home Secretary Priti Patel is expected to set out further details of a “migration and economic development partnership” with Rwanda after she visited the East African nation.
Charities have warned that the “cruel and nasty decision” to “offshore” some asylum seekers more than 6,000 miles away will not only fail to address the issue but “lead to more human suffering and chaos” and cost an estimated £1.4bn.
Mr Johnson will warn the number of people making the crossing across the Channel could reach 1,000 a day within weeks. Around 600 people arrived on Wednesday.
“I accept that these people – whether 600 or 1,000 – are in search of a better life, the opportunities that the United Kingdom provides and the hope of a fresh start,” he is expected to say.
“But it is these hopes – these dreams – that have been exploited. These vile people smugglers are abusing the vulnerable and turning the Channel into a watery graveyard, with men, women and children drowning in unseaworthy boats and suffocating in refrigerated lorries.”
He will argue the country voted to “control” immigration in the Brexit referendum and say “our compassion may be infinite, but our capacity to help people is not”.
“So just as Brexit allowed us to take back control of legal immigration by replacing free movement with our points-based system, we are also taking back control of illegal immigration, with a long-term plan for asylum in this country,” he is expected to say.
“It is a plan that will ensure the UK has a world-leading asylum offer, providing generous protection to those directly fleeing the worst of humanity, by settling thousands of people every year through safe and legal routes.”
It remains unclear if the new rules would apply to only those who arrived by what the government calls illegal means.
The British Red Cross said it was “profoundly concerned” about the plans to “send traumatised people halfway round the world to Rwanda”.
Zoe Abrams, the humanitarian network’s executive director, said: “The financial and human cost will be considerable; evidence from where offshoring has been implemented elsewhere shows it leads to profound human suffering, plus the bill that taxpayers will be asked to foot is likely to be huge.”
She added: “We are not convinced this drastic measure will deter desperate people from attempting to cross the Channel either. People come here for reasons we can all understand, like wanting to be reunited with loved ones, or because they speak the language. Making it harsher may do little to stop them risking their lives.”
Enver Solomon, chief executive of the Refugee Council, said: “Offshoring the UK’s asylum system will do absolutely nothing to address the reasons why people take perilous journeys to find safety in the UK.
“It will do little to deter them from coming to this country, but only lead to more human suffering and chaos – at a huge expense of an estimated £1.4bn a year.”
Several other locations, including Ascension Island, Albania and Gibraltar have previously been rejected.
Government ministers have faced pressure to accept more refugees fleeing Russia’s war in Ukraine and the UK’s visa system has been criticised for being too bureaucratic.