British activists failed in court in their attempt to stop the first deportation flight to Rwanda planned for Tuesday of asylum seekers who had entered the country illegally.
An appeals court in London on Monday rejected an appeal in the case.
Refugee and human rights organizations and the PCS union, which represents British border guards, had complained about the deportation flights.
The British government has struck a deal with Rwanda to fly out illegal migrants to the East African country in exchange for payments.
This is to deter people from trying to enter the UK illegally.
On Friday, the British High Court approved the controversial project in an urgent decision.
The plaintiff organizations immediately appealed, which has now been decided negatively.
According to the government's plans, the first flight with asylum seekers to Rwanda should take off on Tuesday.
The head of the UN refugee agency (UNHCR), Filippo Grandi, strongly condemned the agreement with Rwanda.
It was "completely wrong for so many reasons" and could set a "disastrous" precedent, he told a news conference in Geneva on Monday.
Refugee and human rights organizations and the PCS trade union had also criticized the agreement as immoral, dangerous and counterproductive.
According to a media report, the British heir to the throne Prince Charles had condemned the project as “appalling”.
According to observers, the human rights situation in the East African country is anything but ideal.