The Court of Appeal on Thursday ruled that the UK government's plan to send asylum seekers to Rwanda was unlawful as the African nation could not be considered a safe third country.

Three judges in London said that "unless deficiencies" in Rwanda's asylum system were corrected, "removal of asylum seekers to Rwanda will be unlawful."

Prime Minister Rishi Sunak responded by saying the British government would apply to the UK Supreme Court to challenge the ruling.

"While I respect the court I fundamentally disagree with their conclusions," he said, insisting: "Rwanda is a safe country... We will now seek permission to appeal this decision to the Supreme Court."

Hope Hostel LTD was getting ready to welcome the migrants from United Kingdom (UK) in Kigali, Rwanda. File photo: AFP

The judges agreed with migrants and campaigners who brought the case that the UK government could not guarantee that asylum seekers sent to Rwanda would not be deported to the country from which they were fleeing.

"The deficiencies in the asylum system in Rwanda are such that there are substantial grounds for believing that there is a real risk that persons sent to Rwanda will be returned to their home countries, where they faced persecution or other inhumane treatment," said the judges.

A majority of judges were not convinced by Rwanda's assurances, saying that although made in good faith the evidence they presented "does not establish that the necessary changes had by then been reliably effected or would have been at the time of the proposed removals.

"In consequence, sending anyone to Rwanda would constitute a breach of article 3 of the European Convention on Human Rights" which states that no one shall be subjected to torture, inhuman or degrading treatment or punishment, they added.

The Rwandan government told AFP that it remained committed to the plan.

British Home Secretary Priti Patel (L), and Rwandan Minister of Foreign Affairs and International Cooperation Vincent Biruta, signed a migration and economic partnership agreement at Kigali Convention Center, Kigali, Rwanda in April last year. Photo: AFP

"While this is ultimately a decision for the UK's judicial system, we do take issue with the ruling that Rwanda is not a safe country for asylum seekers and refugees," said government spokeswoman Yolande Makolo. 

Makolo insisted that Rwanda was "one of the safest countries in the world" and said "we have been recognised by the UNHCR and other international institutions for our exemplary treatment of refugees".

Former prime minister Boris Johnson brought in the proposal to try to tackle record numbers of migrants crossing the Channel from northern France by small boats.

But it triggered a wave of protests from rights groups and charities, while last-gasp legal challenges successfully blocked the first deportation flights last June.

Migrants are escorted ashore from a UK Border Force vessel in Dover, southeast England, on June 15. Photo: AFP

Several individuals who arrived in small boats, and organisations supporting migrants, brought a case to the High Court in London, arguing that the policy was unlawful on multiple grounds, including the assessment of Rwanda as a safe third country.

'Rare good news'

Two High Court judges in December dismissed the claims, saying its only remit was "to ensure that the law is properly understood and observed, and that the rights guaranteed by parliament are respected". 

The claimants, 10 asylum seekers from Syria, Iraq, Iran, Vietnam, Sudan and Albania, plus the charity Asylum Aid, then took their case to the Court of Appeal.

The government's vow to take the case to the UK Supreme Court will further put on hold any deportation plans.

Yasmine Ahmed, UK director of Human Rights Watch, called the verdict "some rare good news in an otherwise bleak landscape for human rights in the UK". 

"Rather than treating human beings like cargo it can ship elsewhere, it (the government) should be focusing on ending the hostile environment towards refugees and asylum seekers," she added.

A Boeing 767 had been ready on the runway at the military base in Amesbury, Salisbury, on June 14, 2022, preparing to take a number of asylum-seekers to Rwanda. Photo: AFP

Tackling asylum claims has become a political headache for the ruling Conservative government in London, despite its promise to "take back control" of the country's borders after Britain's departure from the European Union.

More than 11,000 people have already crossed the Channel from northern France this year, while the backlog of asylum claims being processed has reached record levels.

Johnson's short-lived successor Liz Truss and the incumbent Rishi Sunak have backed the Rwanda deal, which aims to send anyone deemed to have entered the UK illegally since January 1 to the African nation.

Sunak and his interior minister Suella Braverman have both said urgent action is needed to break smuggling gangs and to prevent further tragedies in the Channel.

An impact assessment report released this week estimated the plan will cost £169,000 ($210,000) per person, but that most of those costs would be recouped by not having to accommodate the claimants.