Rishi Sunak said the government will appeal the court ruling that the plan to send asylum seekers to Rwanda is illegal.
Court of Appeal judges said Rwanda did not provide sufficient protection to ensure it was a “safe third country”.
The Prime Minister stated that he “fundamentally disagrees” with the decision and said that the government will argue in the Supreme Court.
The charity that came up with the challenge welcomed the decision.
A spokeswoman for Asylum Aid said the decision was “an affirmation of the importance of the rule of law and basic fairness”.
But Mr Sunak said he would do “whatever is necessary” to disrupt gangs operating in small boats while complying with the court’s ruling.
I firmly believe that the Rwandan government has given the necessary assurances to ensure that there is no real risk that asylum seekers who are relocated under Rwandan policy will be mistakenly returned to third countries – something that the Lord Chief Justice would agree with.
“Rwanda is a safe country. The High Court agreed. UNHCR has its own refugee plan for Libyan refugees in Rwanda. We are now seeking permission to appeal this decision to the Supreme Court.”
Interior Minister Suella Braverman said the policy would “break the business model of human trafficking groups”, adding that “I am committed to delivering and will not back down”.
She is expected to respond to the House of Commons decision later.
Rwanda’s government insists it is “one of the safest countries in the world” and has been recognized for its “exemplary treatment of refugees”.
The case involved 10 people from Syria, Iraq and Albania who arrived in the UK on small boats, along with asylum seekers, who argued the policy was illegal.
The decision on whether Rwanda is considered a safe third country for asylum seekers to have their claims considered depends in part on whether there is a risk that people may return to the country they originally left.
The High Court had upheld the government’s policy in an earlier hearing, but the decision was reviewed by Court of Appeal judges Lord Chief Justice Lord Burnett, Sir Geoffrey Voss and Lord Justice Underhill at this final stage of the proceedings.
While Lord Burnett sided with the UK government, others concluded that assurances from the Rwandan government were “insufficient to establish that there is no real risk that asylum seekers who move elsewhere under Rwandan policy will be wrongly deported or returned to their countries of origin.” Other inhumane treatment”.
Deporting asylum seekers to Rwanda is illegal, he said, “until the flaws in the government’s asylum procedures are corrected.”
The judges stressed that their decision had “no political or other views on Rwandan policy” and unanimously said that the Rwandan government’s assurances had been made “in good faith”.
Tessa Gregory, a partner at the law firm Leigh Day, which represented Asylum Aid in the case, said: “We are delighted that the Court of Appeal ruled that Rwanda’s removal process was unlawful on security grounds.”
He admitted that not all of the charity’s challenges had been upheld by the court, but said the decision found there were “clear flaws” in the policy.
Other human rights groups welcomed the court’s decision, with Freedom From Torture describing it as a “victory for reason and compassion”.
Plans to send illegal immigrants to the UK to Rwanda were announced in April 2022 as the government said it aimed to stop people crossing the English Channel in small boats.
But the first exodus flight was canceled after a legal complaint was filed minutes before it was due to take off two months later.
In December, the High Court ruled that the scheme was legal, ruling that it did not breach the UN Refugee Convention – which enshrines the human rights of all asylum seekers.
But next month some of the parties in that case will appeal against aspects of that decision and the case will be heard by the Court of Appeal.
As long as the final decision is satisfied that the Rwandan government is a safe haven for refugees, the UK government’s main immigration policy conflicts with Article 3 of the European Convention on Human Rights, which protects against torture.
Ministers say the policy will prevent thousands of people from illegally crossing the Channel and dismantle human trafficking rings in the process.
This week the Home Office said it expected the Rwanda scheme to cost £169,000 for each person deported and resettled – more than it currently costs to hold an asylum seeker in the UK.
But the same analysis warned that rising accommodation costs could mean the cost of housing an asylum seeker in the UK could be £165,000 per person over four years.
The Home Office says it currently spends around £7m on hotel accommodation to house asylum seekers.
A Downing Street spokesman said he could not “put a timetable on that” when asked if the government was sure the first deportation flight would start after the decision.
Labor’s Yvette Cooper said the policy was “unworkable, unethical and extortionate”.
Liberal Democrat home affairs spokesman Alistair Carmichael said the policy would have done nothing to stop “dangerous Channel crossings” and said Ms Braverman should “accept reality” on the Rwandan plan.