The government had been forced to fight a series of legal challenges in London courts, and believed it was ready to deport a handful of migrants on a charter plane to Rwanda on Tuesday night before the European Court of Human Rights (ECHO) stepped in.
Charities, political opponents and religious leaders have accused the government of waging an "inhumane" battle against asylum seekers. The government argues the policy will smash the business model of people-smuggling networks.
Therese Coffey, work and pensions minister, told British TV the government had been surprised by the intervention but was already preparing for the next flight.
"We still need to obviously go through that ruling, decide the next legal steps but also prepare the next flight," she said.
"The only people who really benefit from this are the traffickers who, frankly as they push the boats out, don't really care if people live or die."
Britain struck a deal with Rwanda in April to sends tens of thousands of asylum seekers to the East African country in what it said was a bid to stem the flow of migrants who make dangerous trips across the English Channel from France.
The United Nations' refugee chief has called the policy "catastrophic", the entire leadership of the Church of England denounced it as immoral, and media reports have said Prince Charles, the heir to the throne, had privately described the plan as "appalling."
Activists block a road leading away from the Colnbrook Immigration Removal Centre as they protest against the British Governments plans to deport asylum seekers to Rwanda, near Heathrow airport in London, June 14, 2022. REUTERS/Henry Nicholls
Prime Minister Boris Johnson said Britain would not be deterred, and the issue has raised demands from some Conservative lawmakers for Britain to pull out of the European Convention on Human Rights altogether.
"Will it be necessary to change some laws to help us as we go along? It may very well be and all these options are under constant review," Johnson said on Tuesday.
The Rwandan government said it remained fully committed to the plan.
"Rwanda stands ready to receive the migrants when they do arrive and offer them safety and opportunity in our country," government spokesperson Yolande Makolo said.