The government of Rwanda on Thursday confirmed that it had signed a “bold new partnership” with the UK under which some people seeking refugee protection in Britain will be transferred to the central African country while awaiting processing.

The announcement comes ahead of a speech in which Prime Minister Boris Johnson will pledge to tackle clandestine migration, particularly in small boats across the English Channel, which has been seen as a significant political problem for his government.

Ministers will also announce plans for a new multimillion-pound processing centre at RAF Linton, a base in North Yorkshire, in an acknowledgment that not all asylum seekers will be sent 4,000 miles away.

However, the Rwanda deal, which has echoes of Australia’s policy of holding clandestine migrants in offshore processing centres, will cause significant controversy because of the human rights implications of removing people seeking asylum.

Rwanda said it would receive an “upfront investment” of £120mn under the deal, which would “fund opportunities for Rwandans and migrants”, including secondary qualifications, vocational and skills training, language lessons, and higher education.

The deal represents the latest effort by the UK under home secretary Priti Patel to deter irregular migration by reducing the rights of those who breach immigration law to reach the UK. It is expected to lead to the transfer of thousands of would-be migrants to the east African country.

The UK detected 28,526 people arriving in the UK via small boats in 2021, a record for peace time. In November, 27 would-be refugees drowned when their boat foundered off the coast of France.

Powers to process migrants overseas are contained in the nationality and borders bill making its way through parliament.

Proposals to process asylum seekers overseas have caused controversy because they contradict longstanding interpretations of the UK’s obligations under the 1951 UN Refugee Convention. This has been seen as obliging countries not to penalise people who breach immigration law to reach their country to make an asylum application.

UNHCR, the UN refugee agency, said on Thursday that it could not comment on the deal but stressed that it “does not support the externalisation of asylum states’ obligations”.

“This includes measures taken by states to transfer asylum-seekers and refugees to other countries, with insufficient safeguards to protect their rights, or where this leads to the shifting rather than the sharing of responsibilities to protect refugees,” it added.

Kigali called the deal, signed between Patel and Rwandan foreign minister Vincent Biruta, the Rwanda-UK Migration and Economic Development Partnership. Rwanda said the agreement would address the “urgent humanitarian crisis” of widespread clandestine migration flows “by tackling its root”.

“By relocating migrants to Rwanda and investing in personal development and employment for migrants, our nations are taking bold steps to address the imbalance in global opportunities which drives illegal migration, while dismantling the incentive structures which empower criminal gangs and endanger innocent lives,” Rwanda said. “The partnership will disrupt the business model of organised crime gangs and deter migrants from putting their lives at risk.

“Migrants will be integrated into communities across the country” and be entitled to “full protection” under local law, equal access to employment, and enrolment in healthcare and social care services, it added.

Rwanda has a tradition of welcoming refugees, and currently hosts about 130,000, mainly from neighbouring Burundi and the Democratic Republic of Congo.

Simon Hart, Welsh secretary, told Sky News that Rwanda was an “up and coming economy” that had “a very good record with migrants”.

“It’s an arrangement which I think suits both countries very well and provides the best opportunities for economic migrants, for those who have been in the forefront of this particular appalling problem for so long now,” he said. “I think that this arrangement has the potential to be a really good step forward and a really humane step forward.”

The deal was strongly criticised by the UK opposition and groups working with refugees.

Yvette Cooper, the shadow home secretary, described the proposal as “a desperate and shameful . . . attempt to distract from his own law breaking”, referring to the “partygate” scandal.

“It is an unworkable, unethical and extortionate policy that 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,” she added.

Tim Naor Hilton, chief executive of Refugee Action, a charity, called the deal a “grubby cash-for-people plan”, which he said would be a “cowardly, barbaric and inhumane way” to treat people fleeing persecution and war.

“Our so-called ‘Global Britain’ is offshoring its responsibilities on to Europe’s former colonies instead of doing our fair share to help some of the most vulnerable people on the planet,” Naor Hilton said.

The plan will also come under scrutiny because it involves the UK sending asylum seekers to a country whose human rights record has been a subject of intense controversy. In July last year, Rita French, the UK’s international ambassador for human rights, criticised Rwanda’s record in a speech to the UN Human Rights Council.

Human rights activists also criticise Paul Kagame, the Rwandan president, for brooking little political dissent. He won the 2017 presidential election with 98.6 per cent of the vote.

New York Press News