(Bloomberg) -- The UK struck a deportation treaty with Rwanda as Prime Minister Rishi Sunak seeks to force his controversial plan to fly asylum seekers to the east African nation past the UK courts.

Home Secretary James Cleverly sealed the deal with his Rwandan counterpart Vincent Biruta in Kigali on Tuesday, telling reporters that the government believes it will allay concerns expressed by British courts, including that deportees faced a risk of “refoulement,” or being forcibly returned to their home country from Rwanda. 

“We feel very strongly that this treaty addresses all the issues raised by their lordships in the Supreme Court,” Cleverly said, referring to last month’s judgment that the deportation policy is unlawful. “I really hope that we can now move quickly,” he said, adding that the pact would be supplemented soon by domestic UK legislation.  Cleverly later told broadcasters he saw “no reason” why deportation flights couldn’t begin in the next few months.

Sunak is focusing on immigration policy as he seeks to chisel away at the double-digit poll lead enjoyed by the opposition Labour Party ahead of a general election he’s expected to call next year. On Monday, Cleverly announced a series of measures designed to cut down the number of people arriving in Britain by legal routes by an annual 300,000. 

But the prime minister has also spent considerable political capital on delivering on the Rwanda plan, which the government regards as a key deterrent against those arriving without permission across the English Channel. Indeed at the start of the year, Sunak made “stopping the boats” one of his five key pledges to voters.

The proposal has been divisive since it was first announced by former ex-premier Boris Johnson in 2022. Refugee charities say the plan doesn’t align with British and international human rights conventions.

“The UK needs to face the facts, open its eyes to Rwanda’s track record of human rights violations, including against refugees and asylum seekers - both domestically and abroad - and abandon its plans to expel asylum seekers to Rwanda once and for all,” Yasmine Ahmed, UK director at Human Rights Watch, said in a statement. Rwanda denies violating human rights in its treatment of asylum seekers.

In the British courts, the government’s strategy fell foul of an inherent contradiction, that ministers simultaneously try to present deportation to Rwanda as both a major deterrent for migrants while also saying the country is a safe enough place to send them to. Last month, the UK Supreme Court decided it wasn’t, and that asylum seekers risked refoulement.

Speaking alongside Cleverly, Biruta said Rwanda had in place a Biruta promised that Rwanda has in place a “fair and transparent system” to deal with the deportees. “The people located to Rwanda will be welcomed” and provided “both the safety and support they need to build their new lives,” he said.

Biruta also said the deal struck with Britain is part of Rwanda’s efforts to help solve a global migration crisis. But the country’s limited capacity means it’s unlikely to scratch the surface of the tens of thousands of asylum seekers who have been reaching UK shores. 

Even so, Cleverly told reporters that Britain has been working with Rwanda for over a year to improve the capacity of its judicial system to deal with the asylum caseload.

The new treaty is the first part of Sunak’s bid to get past the courts. The second, legislation to declare Rwanda safe as an act of Parliament, is expected to be published in the coming days.

The policy is “designed to end the merry-go-round of legal challenges once and for all on this issue,” Immigration Minister Robert Jenrick told BBC Radio on Tuesday. He said that as a result of the new treaty, Parliament will be able to deem Rwanda a “safe” country.

Nevertheless, the policy is far from guaranteed to succeed. Depending on the language of the bill, Sunak is likely to face fierce resistance in the House of Lords, where peers could effectively block it on the basis that the Rwanda plan was not in the Conservative Party’s manifesto at the last general election in 2019.

Alternatively, Sunak could face a backlash from his own party in the House of Commons, if right-wing Tories think the legislation doesn’t go far enough in preventing the Rwanda plan from further legal challenge. Jenrick declined to be drawn on the specifics of the bill.

The issue is totemic for many Conservative MPs, who see reducing immigration as delivering on the UK’s 2016 decision to leave the European Union. On the Tory right, there is the added attraction that hard-line legislation overruling Britain’s international commitments on human rights would be a way to assert sovereignty and the primacy of Parliament — both key Brexiteer arguments.

Tory tensions are running high as attention shifts toward a general election expected next year. Sunak has been locked a debate with his reshuffled Cabinet about how far to push his legislation. Some ministers are concerned about undermining the UK’s international standing, especially as human rights commitments buttress other deals including the Good Friday Agreement, which helped end decades of sectarian violence in Northern Ireland.

The treaty with Rwanda is designed to deal with issues raised by the Supreme Court. Rwanda has already been given £140 million ($178 million) for the program, and Sunak met Rwanda’s president Paul Kagame on the sidelines of the COP28 climate talks in Dubai on Friday. 

--With assistance from Ondiro Oganga, Simon Marks and Andrew Atkinson.

(Updates with Human Rights Watch comment in seventh paragraph.)

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