The decision means that an earlier High Court decision at appellate level from December 2022, which had been in favor of the £140 million Rwanda deal, is hereby officially considered null and void -- at least for the time being.

However, the Court of Appeal specifically tied its decision to the way Rwanda's own existing asylum system is run, saying that the removal of asylum seekers to Rwanda would remain unlawful until changes are made to the asylum system there.

Therefore, the aspect of ruling on the lawfulness of the policy is not a reflection on whether outsourcing asylum processes to third countries is against the law; rather, it specifically means that Rwanda as a country does not meet the UK's standards and can therefore not be considered for the policy at present.

In its ruling, the court specified also that "Article 31 of the Refugee Convention does not in principle prevent the UK from removing asylum-seekers to a safe third country."

Read more: Britain's 'illegal immigration' bill makes progress through parliament

Ruling based on Rwanda's own track record

Lord Chief Justice of England and Wales Ian Burnett said that the court had found "deficiencies" in Rwanda's asylum system, which meant there was a "real risk" that asylum seekers could be returned to their home country and face persecution or inhumane treatment there.

He added that decision had found that "Rwanda is not a 'safe third country'" and that therefore the policy would not comply "with the law as laid down by Parliament."

"Finally, the Court of Appeal makes clear that its decision implies no view whatever about the political merits or otherwise of the Rwanda policy," Lord Burnett highlighted.

The decision comes as a blow for UK Prime Minister Rishi Sunak, whose popularity is tanking amid high inflation and rising interest rates.

Read more: UK: Government hoping to disregard court rulings on migration

No 'cash for humans' deal

The ruling comes after the charity Asylum Aid had brought the case against the government along with ten individual asylum seekers from countries including Syria, Iraq and Albania, who likely would be affected by the policy if it had been ruled lawful.

Asylum Aid said the ruling was a vindication for rule of law and basic fairness.

During the case, the charity had argued that it believed there was a considerable risk that anyone sent to Rwanda could be sent back to their home country if they were rejected.

Another charity involved in the case, Freedom from Torture, said it was "delighted that the appeal verdict has affirmed what the caring people of this country already knew: the UK government's 'cash for humans' deal with Rwanda is not only deeply immoral, it flies in the face of the laws of this country."

Human rights groups have long been calling the idea to send migrants to a small country more than 6,000 kilometers away immoral and inhumane, citing in particular Rwanda's poor human rights record, including allegations of torture and killings of government opponents.

Read more: Suicide risk high among asylum seekers in the UK threatened with removal to Rwanda

Prime Minister vows appeal

Sunak meanwhile has said that his government will try to escalate the case to the next level, seeking permission to appeal the decision at the Supreme Court. 

"While I respect the court I fundamentally disagree with their conclusions," Sunak said, adding that he believed the "Rwandan government has provided the assurances necessary to ensure there is no real risk that asylum seekers relocated under the Rwanda policy would be wrongly returned to third countries."

"The policy of this government is very simple, it is this country – and your government – who should decide who comes here, not criminal gangs. And I will do whatever is necessary to make that happen."

The government now has until July 6 to submit a written appeal, which would later be heard by the UK Supreme Court.

Read more: UK government warned not to embark on Rwanda policy by own advisers

Braverman remains 'fully committed to policy'

UK Home Secretary Suella Braverman issued a statement on the ruling, confirming that the government will seek an appeal.

"We need innovative solutions to smash the business model of the people smuggling gangs, which is why we formed this partnership with Rwanda," she said, adding that she remained "fully committed to this policy as does the Rwandan government."

Earlier this year, the home secretary had declared during a trip to Rwanda that it was her "dream" to see irregular migrants placed on deportation flights to Rwanda.

Read more: Rwanda: 'promised land' for refugees turns out to be a mirage

Criticism from all directions

Braverman's unwavering support for the Rwanda policy has attracted criticism from across the spectrum.

Shadow Home Secretary Yvette Cooper from the Labour Party said "(t)he Rwanda scheme is unworkable, unethical and extortionate, a costly and damaging distraction from the urgent action the government should be taking."

Liberal Democrat Home affairs spokesman Alistair Carmichael the Rwanda asylum plan is not only "immoral, ineffective and incredibly costly for taxpayers, but the Court of Appeal has also now said it is unlawful, too."

Read more: UK spending far more on migrants than on aid for Africa, official figures reveal

Even Conservative Party MP Caroline Nokes, chair of the Women and Equalities Committee of the House of Commons, said earlier in the week that the UK should have better systems set up to deal with asylum seekers than sending them on a one-way ticket to Rwanda.

Nokes noted that with the publicised cost of £169,000 per migrant, the costs outweighed the benefits.

UK director of Human Rights Watch Yasmine Ahmed said the Home Secretary should instead focus her efforts on fixing the UK's "broken and neglected" migration system -- instead of pursuing an "unworkable and unethical fever dream of a policy".

"Rather than treating human beings like cargo it can ship elsewhere, it should be focusing on ending the hostile environment towards refugees and asylum seekers,” she said in a statement.

Read more: She's back: Suella Braverman's return to Home Office mired by controversy

Reactions in Rwanda

Meanwhile, Rwanda has also reacted to the ruling; government spokesperson Yolande Makolo said "we do take issue with the ruling that Rwanda is not a safe country for asylum seekers and refugees."

"Rwanda is one of the safest countries in the world and we have been recognised by the UNHCR and other international institutions for our exemplary treatment of refugees," she added, highlighting that Rwanda accepted the fact that the issue was "ultimately a decision for the UK's judicial system."

She also added that "(e)veryone relocated here under this partnership will benefit from this."

However, Rwandan opposition politician Victoire Ingabire Umuhoza said that she was happy about the decision, highlighting the case of a group of Congolese refugees living at a Rwandan refugee camp who were shot dead by police for protesting against their living conditions.

She told the BBC that Rwanda was not a "safe country," adding that she had spent eight years in prison for not toeing the official line on a number of issues.

"Rwanda is not a freedom country. Anyone who challenges the government's policy and narrative is persecuted."

Read more: Rwanda: Is the climate-vulnerable country prepared to take in more refugees?

With Reuters, AP, AFP, ANSA, BBC