The Court of Appeal has ruled that the British government's plan to deport asylum seekers to Rwanda is unlawful, dealing a setback to Prime Minister Rishi Sunak's campaign to stop migrants crossing the Channel in small boats.

Three senior appeal judges ruled by a majority that Rwanda could not be treated as a safe third country.

Under a deal struck last year, the government planned to send tens of thousands of asylum seekers who arrive on its shores more than 4,000 miles (6,400 km) to the East African country.

The first planned deportation flight was blocked a year ago in a last-minute ruling by the European Court of Human Rights (ECHR), which imposed an injunction preventing any deportations until the conclusion of legal action in Britain.

In December, the High Court ruled the policy was lawful, but that decision was challenged by asylum seekers from several countries such as Syria, Iraq and Iran, along with human rights organizations.

Announcing the Court of Appeal's decision, Judge Ian Burnett said: "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 face persecution or other inhumane treatment."

Burnett said he himself disagreed with the other two judges and a government source said it was likely to challenge the ruling at Britain's Supreme Court. Even if the government was successful there it would mean deportation flights were very unlikely to begin this year.

In the meantime, the ruling is a huge blow for Sunak who is dealing with high levels of inflation, declining public support, and is under increasing pressure from his own party and the public to deal with migrant arrivals in small boats.

Sunak has made "stop the boats" one of five priorities, and is hoping a fall in arrivals might help his Conservative Party pull off an unexpected win at the next national election. 

Sending each asylum seeker to Rwanda would cost on average 169,000 pounds ($213,450), the government said this week.

Last year, a record 45,755 people came to Britain in small boats across the Channel, mainly from France. Over 11,000 have arrived so far this year, a similar rate to the first half of 2022.

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