Boris Johnson is set to unveil the plans later, before Home Secretary Priti Patel signs a migration deal with the African nation.

The trial scheme would mean single men arriving in Britain via Channel crossings could be forcibly removed.

Refugee organisations have criticised the plans as cruel and urged a rethink.

Labour said the plan was "unworkable, unethical and extortionate" - and one designed to "distract" from Mr Johnson's fine for breaking Covid-19 laws.

The Liberal Democrats said the proposal would be "expensive for taxpayers, while doing nothing to stop dangerous Channel crossings or combat the smuggling and trafficking gangs".

The deal is expected to see the Rwanda, which is part of the Commonwealth, given an initial £120m as part of a trial, but opponents say the annual cost of the full scheme would be far higher.

In a speech in Kent, Mr Johnson will argue that action is needed to stop "vile people smugglers" turning the ocean into a "watery graveyard".

Last year, 28,526 people are known to have crossed the English Channel in small boats, up from 8,404 in 2020.

Around 600 people made the crossing on Wednesday, and Mr Johnson will say the figure could reach 1,000 a day within weeks.

"We cannot sustain a parallel illegal system," he will say. "Our compassion may be infinite, but our capacity to help people is not."

The prime minister will announce plans to hand operational control of the Channel to the navy, break the business model of people-smuggling gangs, and deter people from risking the crossing.

The measures are part of the government's long-term plan to "take back control of illegal immigration" after Brexit, Mr Johnson will say.

While the number of people crossing the Channel in boats has increased, last year saw fewer people using other routes - such as by lorry - in part because of increased security at the Port of Calais.

The UK/Rwanda Migration and Development Partnership is the centrepiece of a wider policy blitz to deal with what has been a humiliation for ministers who promised Brexit would mean control of Britain's borders.

Instead, record numbers of asylum seekers have been turning up in dinghies beneath the white cliffs of Dover. This year has already seen 4,578 arrivals and looks set to be a new record.

Sending asylum seekers to Rwanda, however, is likely to prove hugely controversial and legally fraught.

Critics point to Rwanda's poor human rights record. At the UN last year, the UK demanded investigations into alleged killings, disappearances and torture.

Ministers will have to explain why Rwanda is the right place to entrust with protecting the human rights of vulnerable asylum seekers who hoped the UK would protect them.

Opposition in Parliament

The government's Nationality and Borders Bill includes a provision to create offshore immigration processing centres for asylum seekers.

The bill is making its way through Parliament, but with the parliamentary session expected to end within weeks, time is running out to pass it into law.

MPs are currently on a break, but when they return, they are due to review a series of amendments, including one about powers to offshore asylum claims.

The government has suffered a series of defeats in the House of Lords over the bill, which has come in for criticism and sparked protests.

Labour and the SNP have opposed offshoring asylum claims, and the UN's high commissioner for refugees said the practice "would be a breach of the UK's international obligations".

The plan to process asylum seekers abroad was first reported by the Times newspaper last year.

The newspaper said the Home Office had discussed the proposals with their counterparts in Denmark, which has passed legislation allowing it to relocate asylum seekers to countries outside Europe.

'More suffering'

Human rights campaigners have been critical of the plan around its impact on the human rights of refugees, the cost of the scheme and questioned whether it will even achieve its aims.

Enver Solomon, chief executive of the Refugee Council, said the proposal would not "address the reasons why people take perilous journeys to find safety in the UK".

He said the scheme would "only lead to more human suffering, chaos and at huge expense of an estimated £1.4bn a year".

British Red Cross executive director Zoe Abrams said the humanitarian community was "profoundly concerned" about plans to "send traumatised people halfway round the world".

Steve Valdez-Symonds, Amnesty International UK's Refugee and Migrant Rights Director, described the plan as "shockingly ill-conceived idea" which will inflict further suffering and waste "huge amounts" of public money".

Labour's shadow home secretary Yvette Cooper said the policy "would cost the UK taxpayer billions of pounds during a cost of living crisis and would make it harder not easier to get fast and fair asylum decisions".

Alistair Carmichael, home affairs spokesperson for the Liberal Democrats, said the UK had a proud history of providing sanctuary to those in need.

"Thousands of families are opening their homes to refugees, but this Conservative Government is slamming the door in their face," he said.