Can asylum seekers be sent to Rwanda
The five-year trial - announced in April 2022 - would have seen some asylum seekers sent to Rwanda to claim asylum there.
Under the plan, they could be granted refugee status to stay in Rwanda. If not, they could apply to settle there on other grounds, or seek asylum in another "safe third country".
The government said "anyone entering the UK illegally" after 1 January 2022 could be sent there, with no limit on numbers.
Rwanda could also have asked the UK to take in some of its most vulnerable refugees.
The UK has already paid the Rwandan government £140m, but no asylum seeker has actually been sent to the country. The first flight was scheduled to go in June 2022, but was cancelled after legal challenges.
In a major blow to one of Prime Minister Rishi Sunak 's key policies, the country's top court ruled that asylum-seekers sent to Rwanda would be “at real risk of ill-treatment” because they could be returned to the conflict-wracked home countries they'd fled.
The UK Supreme Court ruled unanimously that the Rwanda scheme was unlawful.
Five top justices said the Court of Appeal had been right to conclude in June that there had not been a proper assessment of whether Rwanda was a safe country for asylum seekers.
Lord Reed, the Court president, said there was strong evidence to believe that genuine refugees sent to the country could be at risk of being returned to their home countries where they could face persecution. In law, this is called "refoulement".
It breaches part of the European Convention on Human Rights (ECHR), which prohibits torture and inhuman treatment. The UK is a signatory to the ECHR.
The judges said the policy also breached safeguards in three British laws passed by Parliament over the last 30 years.
The Prime Minister responded to the judgment stating he would introduce emergency legislation declaring Rwanda is a safe country, and that the policy would not be stopped by the European Court of Human Rights (ECtHR). The Supreme Court (or any court, including the ECtHR) cannot strike down an Act of Parliament.