Some migrants could be sent 6,000 miles away to Rwanda, and integrated with communities there.
Human Rights Watch says the proposal is unethical, and cruel.
Brentford Labour MP Ruth Cadbury says it's "cruel and inhumane", while Battersea Labour MP Marsha De Cordova says "it's unnecessarily costly and incredibly cruel".
Prime Minister Boris Johnson says he expects a court challenge, but it’s compliant with international law.